Post on 02-May-2023
1
Mental health problems in adults with Williams syndrome
by
Chris Stinton, Sarah Elison, & Patricia Howlin
Published as
Stinton, C., Elison, S., Howlin, P. (2010). Mental health in adults with Williams syndrome.
American Journal on Intellectual and Developmental Disabilities, 115, 3 – 18.
2
ABSTRACT
Although many researchers have investigated emotional and behavioral difficulties in individuals
with Williams syndrome, few have used standardized diagnostic assessments. We examined
mental health problems in 92 adults with Williams syndrome using the Psychiatric Assessment
Schedule for Adults with Developmental Disabilities—PAS-ADD (Moss, Goldberg, et al., 1996).
Factors potentially associated with mental health problems were also explored. The PAS-ADD
identified mental health problems in 24% of the sample. The most common were anxiety (16.5%)
and specific phobias (12%). Other diagnoses included depression, agoraphobia, and social
phobia. No association was found between the presence of mental health problems and either
individual (e.g., age, IQ, language level) or external (life events) variables.
3
INTRODUCTION
Williams syndrome (WS), a rare genetic disorder caused by a hemizygous deletion of
approximately 26 genes at chromosome 7q 11.23 (Peoples et al., 2000), is typically associated
with positive behavioral characteristics, such as friendliness and sociability (e.g., Bellugi,
Lichtenberger, Jones, Lai, & St. George, 2000; Von Arnim & Engel, 1964). However, emotional
and behavioral difficulties are also common and include inappropriate social behaviors,
preoccupations and obsessions, impulsivity, distractibility, and anxiety (Einfeld, Tonge, & Rees,
2001; Udwin, Yule, & Martin, 1987). Recently, researchers have investigated these problems in
terms of diagnosable psychiatric disorders (Cherniske et al., 2004; Dykens, 2003; Kennedy,
Kaye, & Sadler, 2006; Leyfer, Woodruff-Borden, Klein-Tasman, Frick, & Mervis 2006). Results
of these studies indicate that individuals with WS experience a range of anxiety disorders,
including specific phobias (35 to 54%), agoraphobia (24%), generalized anxiety disorder (12 to
16%), obsessive compulsive disorder (2 to 12%), separation anxiety (4 to 7%), posttraumatic
stress disorder (0.8 to 5%), social phobia (1.7%), and panic disorder with/without agoraphobia
(0.8 to 5%). In those studies in which affective disorders were addressed, the incidence of
depression was reported as being 10 to 14%; dysthymia, 10%; and manic- depressive disorder,
5%. Cases of attention deficit hyperactivity disorder (ADHD, 43%) and sexual impulse control
disorder (5%) have also been reported.
Research into mental health of individuals with WS has been limited by the methods of
assessment used. In many cases, reports of psychopathology have been derived solely from
parental reports or checklists (e.g., Arnold, Yule, & Martin, 1985; Davies, Udwin, & Howlin,
1998; Udwin & Yule, 1991). Other researchers, although employing more detailed measures,
have frequently relied on assessments designed for children (e.g., Dykens, 2003; Kennedy et al.,
2006). These child measures may inflate estimates of mental health problems. For example, in the
Diagnostic and Statistical Manual (DSM) (1994) criteria for the diagnosis of generalized anxiety
disorder in adults, it is stipulated that individuals must find it difficult to control their worry and
show at least three out of six symptoms; children need only display one of the six symptoms.
Conversely, reliance on informant-based interviews (e.g., Dykens, 2003; Leyfer et al., 2006) may
result in underdiagnosis; Moss, Prosser, Ibbotson, and Goldberg (1996) suggested that up to one
third of cases may be missed if information is provided by only an informant or the individuals
4
themselves. Moreover, many of the instruments that have been employed in studies of individuals
with WS have not been validated for use with individuals with intellectual disability.
With occasional exceptions (i.e., Leyfer et al., 2006), most studies have small samples and often
very mixed age groups. Cherniske et al. (2004) had a sample of 20 adults with WS (M age = 39
years) and that of Kennedy et al. (2006), 21 individuals ages 7 to 28 years. Although Dykens’
(2003) sample was larger (N = 51), ages ranged from 5 to 49 years. Small samples limit the
generalizability of findings to the wider population of individuals with WS. Combining data from
young children and adults is also likely to confound the interpretation of results.
Despite these methodological shortcomings, it is evident that there is a high risk of anxiety-
related disorder problems in WS and that there is a need to identify the factors that contribute to
such problems. In studies of mental health problems in other groups of individuals with
intellectual disability, a range of possible risk factors has been identified, including stressful life
events, age, sex, and severity of cognitive impairment. However, the findings are often
contradictory. Thus, although some investigators (e.g., Hastings, Hatton, Taylor, & Maddison,
2004 [adults with intellectual disability]; Coe et al., 1999 [children with Down syndrome])
reported significant correlations between pathology and negative life events, Mantry et al. (2008)
found no significant association between stressful life events and mental health problems in
adults with Down syndrome. Hamilton, Sutherland, and Iacono (2005), in a study of individuals
with autism, cerebral palsy, Down syndrome, and fragile X, found the strength of the association
varied both by diagnostic group and by intellectual level. With regard to age, some researchers
reported a positive correlation between age and rates of mental health problems in individuals
with intellectual disability (Deb, Thomas, & Bright, 2001); others suggested that such problems
are more common in younger individuals or that there are no significant age differences (Cooper,
Smiley, Morrison, Williamson, & Allen, 2007; Espie et al., 2003). The role of sex is also
uncertain. Although much higher rates of mental health problems have been reported in females
in some studies (Cooper et al., 2007; Hastings et al., 2004), others have found no sex-related
differences (e.g., Smiley, 2005; Tsakanikos, Bouras, Sturmey, & Holt, 2006). Similarly, with
respect to intellectual level, although some researchers have reported a positive association
between psychiatric disorder and severity of intellectual impairment (e.g., Cooper et al., 2007;
5
Whitaker & Read, 2006), others have suggested that individuals with mild–moderate
impairments are at greater risk for mental health problems than are those with severe–profound
intellectual disability (Deb et al., 2001; Holden & Gitlesen, 2004; Myrbakk & von Tetzchner,
2008).
Data on the relationship between psychiatric disturbance and other factors, such as physical
health and communication skills, are equally contradictory. Associations between mental health
problems and epilepsy (Espie et al., 2003) or urinary incontinence (Cooper et al., 2007) have
been reported by some researchers; others have failed to find such associations (Deb et al., 2001;
Matthews, Weston, Baxter, Felce, & Kerr 2008; Moss, Patel, et al., 1993). Espie et al.’s (2003)
finding that poorer communication skills were related to emotional–behavioral difficulties has
not been replicated (Cooper et al., 2007; Deb et al., 2001; Matson, Terlonge, González, & Rivet,
2006). Finally, lower rates of mental health problems have been reported among those living with
family members compared to those in other settings, such as group homes (e.g., Cooper et al.,
2007; Deb et al., 2001).
For individuals with WS, the findings are similarly inconclusive. Gosch and Pankau (1997), who
explored the effects of age, found no overall differences in parents’ reported rates of behavioral
disturbance between individuals with WS ages less than 10 years, 10 to 20 years, or over 20
years. However, rates of overt behavioral problems (e.g., destroys objects, hits others,
disobedient, follows strangers) were lowest in the oldest age group, and scores on the withdrawn
item were lowest in the under 10 group. Einfeld et al., (2001), in a 5-year follow-up of 53
children and adolescents with WS, reported a small, but nonsignificant decrease in the total
behavior problem score on the Developmental Behavior Checklist (Einfeld & Tonge, 1995);
scores on the Self-Absorbed subscale had decreased significantly, and repetitive speech had also
decreased. Otherwise, the problems noted at the initial assessment (Einfeld, Tonge, & Florio,
1997) had generally persisted. Dykens (2003) found a significant positive correlation between
age and participants’ total fear scores on the Fear Survey Schedule for Children–Revised
(Ollendick, 1983). Leyfer et al. (2006) found that the proportion of individuals who received a
diagnosis of generalized anxiety disorder was highest in the oldest group (ages 11 to 16 years)
and lowest in the youngest group (ages 4 to 6 years). With regard to sex differences, Dykens
6
(2003) reported that females with WS had significantly higher scores than did males on the Fear
Survey Schedule for Children–Revised; Leyfer et al. (2006) found no sex differences in rates of
mental health problems.
Given the paucity of research regarding mental health in adults with WS, our aims in the present
study were to (a) determine the overall rate of mental health problems in adults with WS using an
assessment measure designed specifically for individuals with intellectual disability, (b)
determine the types of problems and their relative rates in adults with WS, and (c) explore
variables (e.g., adaptive functioning skills, IQ, life events, physical health) that are associated
with psychopathology in other populations in relation to psychopathology in adults with WS.
METHOD
Participants
Potential participants were identified via the United Kingdom Williams Syndrome Foundation
database, and parents of all individuals age 18 and over were contacted regarding participation.
All participants with WS in the study had a diagnosis confirmed by FISH test. The total number
of potential participants was 108. Of these, 8 families could not be contacted, 1 adult with WS
had died, and 7 families did not wish to participate. In total, 92 adults with WS (50 female, 42
male) and their parents (N = 85) or caregivers (N = 7) took part. The mean age of the adults with
WS was 32 years (range = 19 to 55 years).
Assessment Measures
Parental interview. Parents/caregivers of the adults with WS were interviewed on a variety of
topics within the areas of physical health, independence, education, occupation, communication,
social skills, and emotional–behavioral difficulties. Sample questions are provided in the
Appendix. This interview has been employed in previous studies of adults with WS (Davies et
al., 1998; Udwin, Howlin, Davies, & Mannion, 1998).
Psychometric assessments. We assessed IQ using the Wechsler Adult Intelligence Scale-Third
Edition—WAIS-III (Wechsler, 1997) and adaptive behavior using the Vineland Adaptive
Behavior Scale–Interview Edition Survey Form—VABS (Sparrow, Balla, & Cicchetti, 1984).
7
We measured expressive and receptive language using the Expressive One Word Picture
Vocabulary Test–2000 Ed. (Brownall, 2000) and the British Picture Vocabulary Scale–Second
Edition (Dunn, Dunn, Whetton, & Burley, 1997). All of the assessment measures (or earlier
versions of them) had been used in our previous study of adults with WS (Howlin, Davies, &
Udwin, 1998; Udwin, Davies Howlin, & Mannion, 1998).
Psychiatric assessment. We assessed mental health using the Psychiatric Assessment Schedule
for Adults with Developmental Disabilities—PAS-ADD (Moss, Goldberg, et al., 1996). The
PAS-ADD is a semi-structured interview based on the Schedules for Clinical Assessment in
Neuropsychiatry (World Health Organization, 1994). It is designed for use with individuals who
have a range of cognitive impairments (Moss, Patel, et al., 1993; Patel, Goldberg, & Moss, 1993).
Key features pertaining to its use with individuals who have intellectual disability are simplified
wording and the use of a memorable anchor event from the individual’s own life in order to focus
discussion on the previous 4-week period. There are parallel informant–respondent versions that
enable PAS-ADD diagnoses to be produced from the combined information from both interviews
or from either of the interviews separately. The PAS-ADD has a three-tier structure that makes it
suitable for use with individuals who have a range of abilities. The first tier is geared towards
putting the individual at ease and enabling the interviewer to gauge his or her linguistic abilities.
The second tier consists of conceptually simpler questions that make up the minimum items
required for the identification of mental health problems. The third tier consists of the full set of
questions. The PAS-ADD enables International Classification of Diseases—ICD-10 (World
Health Organization, 1994) research diagnoses to be generated for schizophrenia,
undifferentiated psychosis, hypomania, depressive episode, phobic anxiety disorders
(agoraphobia, social phobia, specific phobia), panic disorder, generalized anxiety disorder, and
nonorganic hypersomnia. Most symptoms are rated on a scale of 0 (no symptoms present) to 4
(symptoms of severe intensity). Based on the information provided by informants/respondents,
each item in the PAS-ADD interview is assigned a numerical value. These values are entered into
a computer program (CATEGO-5) that generates ICD-10 diagnoses of psychopathology. The
PAS-ADD also contains a checklist of life events. Parents/caregivers were asked to indicate
whether the individuals with WS had experienced any of these items in the past 2 years.
8
The PAS-ADD has generally good reliability, with a mean kappa of .65 for individual item codes
and .66 for item groups; the correlation between total symptom scores is.74, and the mean kappa
agreement on index of definition,.70 (Costello, Moss, Prosser, & Hatton, 1997). It has good
validity, with comparisons between PAS-ADD- generated diagnoses and diagnoses by referring
psychiatrists reaching 75% agreement (Moss et al., 1997; Moss, Prosser, & Goldberg, 1996).
PAS-ADD Interrater Reliability
In the present study, 20 pairs of interviews (respondent and informant versions) were rated
separately by two raters (the first two authors). Item scores from each of the raters were entered
separately into the CATEGO-5 diagnostic program. Interrater reliability was assessed using
kappas (KappaCom: Robinson, & Bakeman, 1998) and intraclass correlations. Significant
substantial agreement was found for any diagnosis, κ = .68, schizophrenia, κ = .77, depression, κ
= .63, agoraphobia, κ = .77, social phobia, κ = .64, and generalized anxiety disorder, κ = .77. We
found perfect agreement for specific phobia, κ = 1.00, undifferentiated psychosis, κ = 1.00,
hypomania, κ = 1.00, mania, κ = 1.00, and panic disorder, κ = 1.00. The mean kappa agreement
on item groups was .75. The intraclass correlation between index of definition scores (a measure
of the clinical significance of the observed set of behaviors, ranging from 1 to 8) was .83, and the
intraclass correlation between total symptom scores was .98.
Procedure
Assessments took place in parents’ homes and at the homes, day centers, and work places of the
individuals with WS. Typically, assessments began with the parent/caregiver interview, enabling
subsequent assessments to be tailored to suit the ability level of the individual with WS.
Assessments were conducted over a minimum of 2 days. Breaks were taken when requested by
the individual with WS or parents/caregivers or at the discretion of the examiner.
Because of the number and length of the various assessments conducted, we did not feel that it
was appropriate to ask all participants and their parents/caregivers to complete the PAS-ADD.
Instead, the general parent/caregiver interview was used as a screen to indicate which individuals
should be further assessed on this measure. This interview provided preliminary information on a
range of potential mental health problems, with items generally rated on a scale of 0 to 3 (0 = no
9
problem, 1 = some evidence of difficulty in this area but no evidence of distress/interference in
daily life, 2 = evidence of some distress/intrusion in daily life, and 3 = serious problem causing
significant distress/disruption to daily life). For those individuals who scored a 2 or 3 on any of
the mental health items (n = 75, 83% of total sample), we conducted PAS-ADD interviews
separately with the adult with WS (the respondent) and a second person who knew them well (the
informant). Informant-based PAS-ADD assessments were mostly completed with parents, but in
4 cases the informant was a caregiver. Two individuals with WS lacked adequate verbal skills to
complete the PAS-ADD themselves.
RESULTS
Statistics and Significance Level
We used the Statistical Package for the Social Sciences Version 15 for Windows (SPSS 15, 2006)
to conduct our analyses. Parametric or nonparametric tests (one-way ANOVAs, Mann-Whitney,
chi- square tests) were used according to the data analyzed. The level of significance was set at
.01.
Cognitive Characteristics
Full details of cognitive, language, and adaptive functioning of the adults with WS involved in
the study are described in Howlin, Elison, and Stinton (in press). The mean Full Scale IQ of the
adults with WS was 56.6 (SD = 7.2); mean Verbal IQ, 61.7 (SD = 7.4); and mean Performance
IQ, 58.3 (SD = 6.7). The mean receptive vocabulary age equivalent was 10.6 years (SD = 3.7)
and the mean expressive vocabulary age equivalent was 7.4 years (SD = 2.8). The standard score
for the VABS Adaptive Behavior Composite was 40.0 (SD = 16.3).
Emotional–Behavioral Problems
Data from the parent/caregiver interview indicated that 75 individuals with WS, over 80% of the
sample, experienced significant emotional–behavioral difficulties. The most common problems
were distractibility (n = 45, 49%), anxiety (n = 41, 45%), and phobias (n = 43, 47%). Other
problems included mood disturbances (e.g., elevated and depressed moods, 11 to 13%), obsessive
and compulsive behaviors (8%), and psychotic symptoms (e.g., hallucinations, delusions, and
paranoia, 5%). Individuals with these problems had significantly higher IQ, F(1, 87) = 9.84, p =
10
.002, expressive vocabulary, F(1, 90) = 5.91, p = .02, receptive vocabulary, F(1, 90) = 10.72, p =
.002, and Adaptive Behavior Composite scores, F(1, 89) = 18.07, p < .001, than those without
emotional–behavioral problems.
PAS-ADD Diagnoses: Informant or Respondent Version
On the basis of the information derived from the parent/caregiver interview, we administered the
PAS-ADD to 75 individuals. Based on the combined data from the respondent interview and the
informant interview (i.e., where a diagnosis came from either interview), we found that 22 adults
with WS (24% of total sample) had at least one PAS-ADD diagnosis. The most commonly
identified problem was specific phobia (12%) followed by depression (9%). Specific phobias
were of storms (n = 6), hospitals (n = 2), dentists (n = 1), heights (n = 1), and wasps (n = 1).
Other PAS-ADD diagnoses are shown in Table 1. Fifteen adults (16% of the total sample)
received a PAS-ADD diagnosis for any anxiety disorder.
+++++++++ Table 1 here ++++++++++
Comorbidity was common, with 9 adults receiving two or more PAS-ADD diagnoses. Of these
individuals, 6 received two PAS-ADD diagnoses, 2 received three diagnoses, and 1 received four
PAS-ADD diagnoses (see Table 2). Typically, these were for multiple anxiety disorders or
anxiety disorders with depression.
+++++++++ Tables 2 and 3 here ++++++++++
Agreement: Informant Versus Respondent
There was little agreement between PAS-ADD diagnoses from respondent and informant
interviews. If the PAS-ADD diagnoses obtained from both informant interview and respondent
interview were included, 9 adults with WS (9.8% of total sample) received a PAS-ADD
diagnosis. The most common problems were depression (n = 4) and specific phobias (n = 3).
There were isolated cases of agoraphobia, panic disorder, generalized anxiety disorder, and
undifferentiated psychosis. Five of the sample received a PAS-ADD diagnosis of any anxiety
disorder (see Table 1). Two individuals received multiple diagnoses (see Table 2). The level of
11
agreement for any diagnosis between parent/caregiver and adult with WS was not related to
respondents’ sex, p = .51 (Fisher’s Exact), IQ, F (1, 84) = 2.74, p = 1.01, receptive vocabulary,
F(1, 87) = 3.66, p = .06, or expressive vocabulary, F(1, 86) = 1.95, p = .17), or to whether the
adult with WS was living at home with parents, p = .86 (Fisher’s Exact).
Mental Health and Pharmacological Treatments
The parent/caregiver interview provided information on the medications prescribed for
emotional, behavioral, or mental health problems. In total, 11 participants were receiving
pharmacological treatments: 6 for depression, 2 for anxiety, and 3 for combined anxiety and
depression. The medications prescribed were fluoxetine (n = 3), diazepam (n = 3), paroxetine (n
= 3), citalopram (n = 2), sertraline (n = 2), venlafaxine (n = 2), chlorpromazine (n = 2),
escitalopram (n = 1), and carbamazepine (n = 1). Three participants were taking more than one
type of medication. Because the PAS-ADD does not cover whether medication is taken (which
may, of course, prevent overt symptoms), the true rate of mental health problems may have been
underestimated. To investigate whether this was the case, we further examined the PAS-ADD
diagnoses of individuals who were receiving pharmacological treatment. Five adults who were
currently taking medication for mental health problems (3 for depression, 1 for anxiety, and 1 for
depression and anxiety) did not receive any PAS-ADD diagnoses. Of the remainder, 2 were
taking medication for depression (both received PAS-ADD diagnoses of depression and anxiety);
1 (diagnosis of depression) was taking antidepressants; 1 (diagnosis of depression) was receiving
medication for depression and anxiety; 1 (diagnosis hypomania) was receiving medication for
anxiety, and 1 (diagnoses anxiety and schizophrenia) was taking medication for depression. If
those individuals who were not exhibiting overt symptoms but were taking prescribed medication
were included in the assessment of diagnosable mental health problems, then there may have
been an additional 4 cases of depression and an additional 2 cases of anxiety. Including
individuals who were receiving psychotropic medication as well as those who met PAS-ADD
criteria would bring the total number of individuals with diagnosable mental health problems to
27 (29%), giving a rate of 13% (n = 12) for depression and 19% (n = 17) for any anxiety disorder.
12
Variables Associated With Mental Health Problems
Life Events
Over the preceding 2 years, 59 participants (69%) had experienced one or more stressful life
event. The most common events were death of or serious illness/injury to a close relative/friend,
followed by serious problems with a close relative/friend, serious illness/injury to self, move of
residence, and break up of relationship (see Table 3). There were no significant differences in the
number of life events experienced by individuals who received a PAS-ADD diagnosis and those
who did not, U = 542, z = -1.36, p = .17.
Other Variables
Other factors potentially related to mental health problems were also considered. These were age,
sex, expressive vocabulary, receptive vocabulary, IQ, health, adaptive behavior, and residential
status. No specific hypotheses were made regarding their impact in view of limited information
on predictors of mental health problems in this group. For all analyses, we based diagnosis on
combined data (i.e., when a PAS-ADD diagnosis came from either the informant interview or the
respondent interview).
Chi-square tests indicated that there were no significant associations between mental health status
and sex or living arrangements (see Table 4). One-way ANOVA tests indicated that there were
no significant differences between participants who received a PAS -ADD diagnosis and those
who did not in terms of age, F(1, 89) = .017, p = .90, IQ, F(1, 86) = .07, p = .80, receptive
vocabulary, F(1, 89) = .43, p = .51, expressive vocabulary F(1, 88) = .01, p = .95, or Adaptive
Behavior Composite standard score, F(1, 89) = .53, p = .47. (see Table 5).
+++++++++ Tables 4 and 5 here ++++++++++
DISCUSSION
Individuals with WS experience more emotional, behavioral, and mental health problems and
have higher rates of anxiety disorders (particularly specific phobias) than do the general
population and many other groups who have intellectual disability (e.g., Dykens, 2003).
13
However, previous studies are often limited by methodological issues (e.g., small samples, broad
age range of participants, and the use of assessment measures designed for typically developing
populations). In this study we addressed these issues and examined factors associated with mental
health problems in the largest study to date of mental health in adults with WS.
Parent/caregiver reports indicated that 83% of the adults with WS experienced emotional or
behavioral problems that resulted in some degree of distress or disruption to daily life. These
included anxiety, fears and phobias, distractibility, hallucinations, and compulsive behavior.
Almost one quarter of the sample (24%) met PAS-ADD criteria for any psychiatric disorder and a
further 5 individuals were currently receiving psychotropic medication for diagnosed mental
health problems. Thus, in total 29% of the cohort had a diagnosable, or currently diagnosed,
psychiatric disorder. Consistent with prior research findings, anxiety disorders were common,
with 16.5% receiving a diagnosis for any anxiety disorder and 12%, for specific phobia. Other
anxiety problems identified were agoraphobia, panic disorder, social phobia, and generalized
anxiety disorder (ranges = 1 to 4%). The most common nonanxiety diagnosis was depression
(9%). There was a small number of cases of hypomania (3%), schizophrenia (2%), and
undifferentiated psychosis (1%). Nine (41%) of the 22 people with a psychiatric disorder had
multiple psychiatric diagnoses.
Comparisons With Previous Research
Comparisons of mental health problems across studies are compromised by the lack of
consistency in the methods and instruments used. Nevertheless, rates of panic disorder, social
phobia, and depression in the present study were similar to those reported previously. Results of
the present study also corroborate findings from earlier research indicating higher rates of
depression in WS (9 to 14%) compared with individuals who have intellectual disability of
mixed/unknown etiology (2 to 7%: Cooper, 1997; Cooper et al., 2007; Deb et al., 2001).
Rates somewhat lower than previously reported were found for other types of mental health
problems, although frequency estimates in other studies of WS also vary (from rates of 48 to 65%
for any anxiety disorder, 35 to 54% for specific phobias, and 12 to 24% for generalized anxiety
disorder: Cherniske et al., 2004; Dykens, 2003; Kennedy et al., 2006; Leyfer et al., 2006).
14
Differences are likely due to a number of different factors. Sampling is important and because the
present study involved a large proportion of the adults identified with WS in the United
Kingdom, it provides a more representative sample than do many other studies. Further, this is
the only research in which a psychiatric interview specifically designed for adults with
intellectual disability was employed.
Other possible reasons for lower rates of some types of mental health problems in the present
study compared to prior research, particularly for anxiety, are age of the sample and families’
experiences of dealing with anxiety over a long period of time. Anecdotally, some parents
reported that although their son or daughter had experienced anxiety over the years, as parents
they had developed strategies to reduce this anxiety (e.g., not giving too much advanced warning
about potentially worrying events or changes to regular routine). Some parents also reported that
issues that had previously been a source of distress had later become a source of interest. For
example, one parent spoke of how her son had become fascinated with cleaning equipment (e.g.,
vacuum cleaners, washing machines) despite being very upset when he was younger by the
noises they made.
Nevertheless, there was also some evidence from the parent/caregiver interview that other
disorders, notably specific phobias and generalized anxiety disorder, may have been
underdiagnosed by results on the PAS-ADD. For example, on the parent interview, 47% of adults
with WS were reported as having fears/phobias, and 45% were reported as having a tendency to
worry about seemingly trivial things. However, the severity of these problems did not meet PAS-
ADD diagnostic criteria and, as such, these high rates of parent/caregiver reported anxiety may
reflect an anxious disposition in adults with WS rather than diagnosable anxiety disorders.
A further problem relating to the PAS-ADD is that it does not cover certain types of mental
health problems identified in other studies of individuals with WS. These include ADHD (e.g.,
Kennedy et al., 2006; Leyfer et al., 2006), dysthymia (Kennedy et al., 2006), manic depression
(Cherniske et al., 2004), obsessive compulsive disorder (Cherniske et al., 2004; Leyfer et al.,
2006), posttraumatic stress disorder (Kennedy et al., 2006; Leyfer et al., 2006), separation anxiety
(Dykens, 2003; Kennedy et al., 2006; Leyfer et al., 2006), and sexual impulse disorder
15
(Cherniske et al., 2004). Formal diagnoses of these disorders were, thus, not possible, although
some of these issues arose in the parent/caregiver interview. Indeed, the most frequent problem
reported by parents/caregivers was distractibility (49%), a component of ADHD. Approximately
8% of the adults with WS were reported as displaying obsessive and compulsive behaviors (e.g.,
excessive interest in famous people, insistence on following set routines). Changeable mood was
reported as a problem by parents of 11% of the sample. One participant had previously received
treatment for posttraumatic stress disorder following a car accident.
Although the PAS-ADD may have underdiagnosed some conditions, rates of agoraphobia (4%)
were considerably higher than the less than 1% rates reported by Leyfer et al. (2006) or for
individuals with intellectual disability more generally (Cooper et al., 2007; Emerson, 2003).
Again, differences in sample selection may account for this finding. For example, rates of
agoraphobia in individuals with intellectual disability are approximately twice as high in adults as
children (Cooper et al., 2007; Emerson, 2003). Thus, among older adults with WS, rates of
agoraphobia are likely to be higher than those found for younger participants with WS.
Other mental health problems (i.e., undifferentiated psychosis, 1%; schizophrenia, 2%; and
hypomania, 3%) not previously reported in individuals with WS were identified in the present
study. These rates are comparable to those reported for individuals with intellectual disability of
unknown etiology in whom schizophrenia occurs in between 1 to 6% and hypomania, in 2 to 7%
(e.g., Clarke, 2007; Cooper et al., 2007; Moss et al., 2000). Failure to identify these relatively
uncommon problems in other WS studies is most likely due to the small sample sizes involved
(e.g., N = 20, Cherniske et al., 2004; N = 51, Dykens, 2003; N = 21, Kennedy et al., 2006). In
addition, many of these studies have included children for whom rates of psychotic disorders are
even lower (Emerson, 2003).
Factors Associated With Mental Health Problems in Williams Syndrome
It is well-established that stressful life events are more common among individuals with
intellectual disability than in the general population, and such events are associated with
emotional, behavioral, and mental health problems (e.g., Hastings et al., 2004; Hatton &
Emerson, 2004). Nevertheless, although nearly 70% of adults with WS in the present study had
16
experienced at least one such event in the preceding 2 years, there was no significant association
with mental health status. In addition, we found no correlation between diagnosed mental health
problems and variables such as age, sex, IQ, adaptive functioning, physical health, or residential
status. Additionally, Kennedy et al. (2006) found no relationship with a family history of
psychiatric disorders. This lack of association with family or environmental factors, together with
the high rates of anxiety and attention disorders in WS, led Kennedy et al. (2006) to propose that
such problems may be caused by or related to the specific WS genotype. However, not all
individuals with WS experience mental health problems and, clearly, such problems cannot be
attributed to genetic factors alone. The cumulative effects of other social, environmental, and
individual factors (including personality type) that have been shown to be associated with mental
health problems in other populations still require systematic research.
Discrepancy Between Respondent and Parent/Caregiver Informant Reports
In the present study, agreement between informant and respondent reports of psychopathology
was low. Diagnoses of anxiety disorders (specific phobia, agoraphobia, panic disorder, and social
phobia) were more frequently derived from self reports; affective disorders (depression and
hypomania) were more frequently identified by informants.
Poor agreement between self and informant reports of mental health problems poses a significant
challenge to psychiatric research generally (cf. Heun, Kockler, Papassotiropoulos, & Fimmers,
2006; Kraemer et al., 2003; Rougemont-Buecking et al., 2008). Such problems are likely to be
exacerbated if respondents have additional language or cognitive problems that affect their ability
to report internal feelings. Moss, Prosser, Ibbotson, and Goldberg (1996) found that in only 41%
of cases did diagnoses based on the informant and the respondent information agree, with
respondents who have intellectual disability being more likely to report autonomic symptoms and
certain aspects of psychosis (e.g., hallucinations) and informants more frequently reporting
symptoms of anxiety and depression (e.g., social withdrawal, irritability, and nervous tension).
Dykens (2003) also noted that agreement between individuals with WS and their parents was
poor, r = .20. Freeman, Williams, Farran, and Brown (2008) found that individuals with WS and
their parents reported similar levels of difficulties (emotional symptoms) and strengths (prosocial
behaviors) on the Strengths and Difficulties Questionnaire (Goodman, 1999), but there were
17
significant differences in their ratings of peer relationship problems and hyperactivity/inattention.
Further, parents reported problems as having a greater impact than did the individuals with WS.
Other researchers have highlighted differences in the types of information that are reported by
informants and respondents. Bramston and Fogarty (2000) suggested that certain emotions
experienced by people with intellectual disability, such as fear, guilt, and loneliness, may be
difficult for another individual to identify. Moss, Prosser, Ibbotson, and Goldberg (1996) noted
that informants may have difficulties in identifying anxiety disorders when the PAS-ADD is used
because diagnostic criteria include autonomic symptoms of which they may be unaware. In the
present study some parents/caregivers reported that they were unable to identify symptoms such
as racing heart, dry mouth, and dizziness. There are specific features of the WS phenotype that
may further add to these problems. Although concrete language is relatively good, more abstract
aspects of language are impaired (Mervis & John, 2008), and certain deficits in “theory of mind”
have been identified (Porter, Coltheart, & Langdon, 2008) that could well reduce individuals’
ability to report internal states. On the other hand, there is a suggestion that people with WS have
a tendency to over report fears and anxiety, possibly because of their desire to please the
interviewer (Dykens, 2003).
Although the current findings indicate the importance of including the perspectives of both
informants and respondents, how to overcome potentially conflicting biases of this kind and
reach a reliable estimate of mental health problems remains a major challenge. In determining
whether to offer interventions (particularly those involving medication or even in-patient
treatment), should clinicians rely on informant reports or those of the individual with intellectual
disability? For example, if parents are convinced there is a problem and the individual insists that
there is none (or vice-versa), what is the appropriate clinical response? In these circumstances a
different approach to assessment may be warranted (e.g., employing a measure where the focus is
on significant changes in patterns of behavior or mood compared to the individual’s usual
symptoms and behavioral repertoire). The Diagnostic Criteria for Psychiatric Disorders for Use
with Adults with Learning Disabilities/Mental Retardation—DC-LD (Royal College of
Psychiatrists, 2001) and the Schedule for Assessment of Psychiatric Problems Associated with
18
Autism—SAPPA (Bolton, & Rutter, 1994) both use this approach, although research into the
reliability and validity of these instruments remains limited.
Other Methodological Limitations
This study has a number of limitations. The validity of the PAS-ADD has been questioned in
relation to anxiety disorders, with some researchers suggesting that anxiety disorders are
underdiagnosed using this instrument (Moss et al., 1997) and others that it overdiagnoses them
(Gonzalez-Gordon, Salvador-Carulla, Romero, Gonzalez-Saiz, & Romero, 2002). Further, the
ICD-10 criteria for psychiatric disorders, on which the PAS-ADD is based, were designed for
typically developing populations. Although these criteria may be applicable for individuals with
mild intellectual disability (Sovner & Hurley, 1983), they do not allow consideration of behaviors
that may form part of the behavioral phenotype of certain genetic disorders (see Mohr &
Costello, 2007, for discussion of these and other diagnostic issues related to intellectual
disability). Again, further refinement of instruments such as the DC-LD or SAPPA might play an
important role here.
There are also limitations in the approach we used to assess life events. We obtained this
information from parents/caregivers, but standardized life event schedules have recently been
developed for individuals with intellectual disability (e.g., the Bangor Life Events Schedules for
Intellectual Disabilities: Williams et al., 2006 ED: ) and the Lifestress Inventory: Lunksy &
Bramston, 2006). These were not available when our study began. A further issue is that life
events were measured only in terms of their presence or absence; factors such as the frequency or
impact of those events were not considered, although these may have a greater association with
emotional, behavioral, and mental health problems (Esbensen & Benson; 2006). Moreover,
although life events are generally assumed to be negative, this is not always the case. For
example, depending upon the circumstances, a move of residence could be a very positive
experience.
The fact that the PAS-ADD diagnostic interviews were only administered if initial screening on
the parent/caregiver interview indicated the presence of mental health problems also raises issues.
First, we do not know whether a screening interview conducted with the individuals who have
19
WS would have elicited the same information. Second, because PAS-ADD interviews were only
completed for individuals reported as having emotional–behavioral difficulties, this might have
biased interviewers towards identifying more mental health problems on this measure. Third,
individuals who were not interviewed with the PAS-ADD were included in the no diagnosis
group. It is possible that if these individuals had been interviewed with the PAS-ADD, the rates
of mental health problems identified would have increased. However, this is unlikely because
although over 80% of the adults were described on the parent/caregiver interview as displaying
emotional–behavioral difficulties, only about a quarter of the sample met criteria for a psychiatric
disorder on the PAS-ADD. This suggests that it is extremely unlikely that individuals who were
reported by parents/caregivers as having no significant emotional or behavioral difficulties would
have fulfilled PAS-ADD diagnostic criteria. Nevertheless, this possibility cannot be ruled out.
Finally, it is necessary to exercise caution concerning the apparent lack of statistically significant
associations between mental health problems and the variables investigated in the present
research. First, the number of participants in the diagnosis group was relatively small, thus
reducing the statistical power to identify significant associations. Second, the focus on the
relationship between individual variables and mental health problems may have masked the
cumulative effects of multiple risk factors. The use of binary logistic regression might have
proved a solution to this problem, but the sample size was not appropriate for this type of analysis
(cf. Peduzzi, Concato, Kemper, Holford, & Feinstein, 1996), and this would have been the case
even if all of the possible participants had agreed to take part in the study. Although research in
which much larger samples are used is clearly needed to explore the complex relations between
mental health and multiple risk factors, this presents further problems when rare disorders are
involved.
Despite such caveats, the major strength of this study is that the findings are derived from a large
and exclusively adult sample of individuals, all of whom had received a genetic confirmation of
WS. In previous studies of emotional and mental health problems, researchers have relied on data
from smaller samples (not all of whom have genetic confirmation) and most also involve younger
participants or a mix of both adults and children. Rates and types of such disorders can change
significantly with age, and data on problems that are specific to adulthood had not previously
20
been available. Finally, we assessed mental health using a measure designed specifically for
individuals with intellectual disability.
In summary, this research adds significantly to the knowledge base regarding mental health in
adults with WS. It is clear from parent/caregiver reports that a large proportion of adults with WS
experience emotional–behavioral difficulties that cause at least some distress or intrusion into
everyday life. Results of the PAS-ADD indicated that anxiety, fears, and phobias—of a severity
that meets diagnostic criteria for psychiatric disorder—are relatively common and occur more
frequently than in the general population or other groups of individuals with intellectual
disability. None of the factors investigated (e.g., life events) was found to be associated with
mental health problems, possibly suggesting that WS may be associated with a particular
behavioral phenotype that includes a predisposition towards anxiety.
21
REFERENCES
American Psychiatric Association. (1994). Diagnostic and statistical manual (4th ed.).
Washington, DC: Author.
Arnold, R., Yule, W., & Martin, N. (1985). The psychological characteristics of infantile
hypercalcemia—A preliminary investigation. Developmental Medicine and Child
Neurology, 27, 49–59.
Bellugi, U., Lichtenberger, L., Jones, W., Lai, Z., & St. George, M. (2000). The neurocognitive
profile of Williams syndrome: A complex pattern of strengths and weaknesses. Journal of
Cognitive Neuroscience, 12, 7–29.
Bolton, P., & Rutter, M. (1994). Schedule for Assessment of Psychiatric Problems Associated
with Autism (and Other Developmental Disorders) (SAPPA). Cambridge: University of
Cambridge; London: Institute of Psychiatry.
Bramston, P., & Fogarty, G. (2000). The assessment of emotional distress experienced by people
with an intellectual disability: A study of different methodologies. Research in
Developmental Disabilities, 21, 487–500.
Brownall, R. (2000). Expressive One Word Picture Vocabulary Test. Novato, CA: Academic
Therapy Publications.
Cherniske, E. M., Carpenter, T. O., Klaiman, C., Young, E., Bregman, J., Insogna, K., et al.
(2004). Multisystem study of 20 older adults with Williams syndrome. American Journal
of Medical Genetics Part, 131A, 255–264.
Clarke, D. (2007). Schizophrenia spectrum disorders in people with intellectual disabilities. In N.
Bouras & G. Holt (Eds.), Psychiatric and behavioural disorders in intellectual and
developmental disabilities (2nd ed., pp. 131–142). Cambridge: Cambridge University
Press.
Coe, D. A., Matson, J. L., Russell, D. W., Slifer, K. J., Capone, G. T., Baglio, C., et al. (1999).
Behavior problems of children with Down syndrome and life events. Journal of Autism
and Developmental Disorders, 29, 149–156.
Cooper, S. A. (1997). Psychiatry of elderly compared to younger adults with intellectual
disabilities. Journal of Applied Research in Intellectual Disabilities, 10, 303–311.
22
Cooper, S. A., Smiley, E., Morrison, J., Williamson, A., & Allan, L. (2007). Mental ill-health in
adults with intellectual disabilities: Prevalence and associated factors. British Journal of
Psychiatry, 190, 27–35.
Costello, H., Moss, S., Prosser, H., & Hatton, C. (1997). Reliability of the ICD-10 version of the
Psychiatric Assessment Schedule for Adults with Developmental Disability (PAS–ADD).
Social Psychiatry and Psychiatric Epidemiology, 32, 339–343.
Davies, M., Udwin, O., & Howlin, P. (1998). Adults with Williams syndrome–Preliminary study
of social, emotional and behavioural difficulties. British Journal of Psychiatry, 172, 273–
276.
Deb, S., Thomas, M., & Bright, C. (2001). Mental disorder in adults with intellectual disability. I:
Prevalence of functional psychiatric illness among a community-based population aged
between 16 and 64 years. Journal of Intellectual Disability Research, 45, 495–505.
Dunn, L. M., Dunn, L. M., Whetton, C., & Burley, J. (1997). British Picture Vocabulary Scale–
Second Edition. Windsor, NFER-NELSON.
Dykens, E. M. (2003). Anxiety, fears, and phobias in persons with Williams syndrome.
Developmental Neuropsychology, 23, 291–316.
Einfeld, S. L., & Tonge, B. J. (1995). The Developmental Behaviour Checklist: The development
and validation of an instrument to assess behavioural and emotional disturbance in
children and adolescents with mental retardation. Journal of Autism and Developmental
Disorders, 25, 81–104.
Einfeld, S. L., Tonge, B. J., & Florio, T. (1997). Behavioral and emotional disturbance in
individuals with Williams syndrome. American Journal on Mental Retardation, 102, 45–
53.
Einfeld, S. L., Tonge, B. J., & Rees, V. W. (2001). Longitudinal course of behavioral and
emotional problems in Williams syndrome. American Journal on Mental Retardation,
106, 73–81.
Emerson, E. (2003). Prevalence of psychiatric disorders in children and adolescents with and
without intellectual disability. Journal of Intellectual Disability Research, 47, 51–58.
Esbensen, A. J., & Benson, B. A. (2006). A prospective analysis of life events, problem
behaviours and depression in adults with intellectual disability. Journal of Intellectual
Disability Research, 50, 248–258.
23
Espie, C. A., Watkins, J., Curtice, L., Espie, A., Duncan, R., Ryan, J. A., et al. (2003).
Psychopathology in people with epilepsy and intellectual disability: An investigation of
potential explanatory variables. Journal of Neurology, Neurosurgery and Psychiatry, 74,
1485–1492.
Freeman, K., Williams, T., Farran, E. K., & Brown, J. (2008). Williams syndrome: The extent of
agreement between parent and self report of psychological difficulties. Manuscript
submitted for publication.
Gonzalez-Gordon, R. G., Salvador-Carulla, L., Romero, C., Gonzalez-Saiz, F., & Romero, D.
(2002). Feasibility, reliability and validity of the Spanish version of Psychiatric
Assessment Schedule for Adults with Developmental Disability: A structured psychiatric
interview for intellectual disability. Journal of Intellectual Disability Research, 46, 209–
217.
Goodman, R. (1999). The extended version of the Strengths and Difficulties Questionnaire as a
guide to child psychiatric caseness and consequent burden. Journal of Child Psychology
and Psychiatry and Allied Disciplines, 40, 791–799.
Gosch, A., & Pankau, R. (1997). Personality characteristics and behaviour problems in
individuals of different ages with Williams syndrome. Developmental Medicine and Child
Neurology, 39, 527–533.
Hamilton, D., Sutherland, G., & Iacono, T. (2005). Further examination of relationships between
life events and psychiatric symptoms in adults with intellectual disability. Journal of
Intellectual Disability Research, 49, 839–844.
Hastings, R. P., Hatton, C., Taylor, J. L., & Maddison, C. (2004). Life events and psychiatric
symptoms in adults with intellectual disabilities. Journal of Intellectual Disability
Research, 48, 42–46.
Hatton, C., & Emerson, E. (2004). The relationship between life events and psychopathology
amongst children with intellectual disabilities. Journal of Applied Research in Intellectual
Disabilities, 17, 109–117.
Heun, R., Kockler, M., Papassotiropoulos, A., Ptok, U., & Fimmers, R. (2006). Subject and
informant characteristics influence the reliability and validity of family history
information: An analysis based on the generalized estimating equations approach.
International Journal of Methods in Psychiatric Research, 9, 60–67.
24
Holden, B., & Gitlesen, J. P. (2004). The association between severity of intellectual disability
and psychiatric symptomatology. Journal of Intellectual Disability Research, 48, 556–
562.
Howlin, P., Davies, M., & Udwin, O. (1998) Cognitive functioning in adults with Williams
syndrome, Journal of Child Psychology and Psychiatry, 39, 183–189.
Howlin, P., Elison, S., & Stinton, C. (in press). Cognitive , linguistic and adaptive functioning in
adults with Williams syndrome. Journal of Applied Research in Intellectual Disabilities.
Kennedy, J. C., Kaye, D. L., & Sadler, L. S. (2006). Psychiatric diagnoses in patients with
Williams syndrome and their families. Jefferson Journal of Psychiatry, 20, 22–31.
Kraemer, H. C., Measelle, J. R., Ablow, J. C., Essex, M. J., Boyce, W. T., & Kupfer, D. J.
(2003). A new approach to integrating data from multiple informants in psychiatric
assessment and research: Mixing and matching contexts and perspectives. American
Journal of Psychiatry, 160, 1566–1577.
Leyfer, O. T., Woodruff-Borden, J., Klein-Tasman, B. P., Fricke, J. S., & Mervis, C. B. (2006).
Prevalence of psychiatric disorders in 4 to 16-year-olds with Williams syndrome.
American Journal of Medical Genetics –Neuropsychiatric Genetics, 141B, 615–622.
Lunksy., & Bramston, P. (2006). A preliminary study of perceived stress in adults with
intellectual disabilities according to self-report and informant ratings. Journal of
Intellectual, & Developmental Disability, 31, 20–27.
Mantry, D., Cooper, S. A., Smiley, E., Morrison, J., Allan, L., Williamson, A., et al. (2008). The
prevalence and incidence of mental ill-health in adults with Down syndrome. Journal of
Intellectual Disability Research, 52, 141–155.
Matson, J. L., Terlonge, C., González, M. L., & Rivet, T. (2006). An evaluation of social and
adaptive skills in adults with bipolar disorder and severe/profound intellectual disability.
Research in Developmental Disabilities, 27, 681–687.
Matthews, T., Weston, N., Baxter, H., Felce, D., & Kerr, M. (2008). A general practice-based
study of epilepsy among adults with intellectual disabilities and of its association with
psychiatric disorder, behaviour disturbance and carer stress. Journal of Intellectual
Disability Research, 52, 163–173.
25
Mervis, C. B., & John, A. E. (2008). Vocabulary abilities of children with Williams syndrome:
Strengths, weaknesses, and relation to visuospatial construction ability. Journal of Speech
Language and Hearing Research, 51, 967–982.
Mohr, C., & Costello, H. (2007). Mental health assessment and monitoring tools for people with
intellectual disabilities. In N. Bouras & G. Holt (Eds.), Psychiatric and behavioural
disorders in intellectual and developmental disabilities (2 ed., pp. 24–41). Cambridge:
Cambridge University Press.
Moss, S., Goldberg, D., Patel, P., & Wilkin, D. (1993). Physical morbidity in older people with
moderate, severe and profound mental handicap, and its relation to psychiatric morbidity.
Social Psychiatry and Psychiatric Epidemiology, 28, 32–39.
Moss, S., Goldberg, D., Patel, P., Prosser, H., Ibbotson, B., Simpson, N., et al. (1996). The
Psychiatric Assessment Schedule for Adults with Developmental Disabilities. Manchester,
England: University of Manchester, Hester Adrian Research Centre.
Moss, S., Patel, P., Prosser, H., Goldberg, D., Simpson, N., Rowe, S., et al. (1993). Psychiatric
morbidity in older people with moderate and severe learning disability 1. Development
and reliability of the patient interview (PAS–ADD). British Journal of Psychiatry, 163,
471–480.
Moss, S., Prosser, H., & Goldberg, D. (1996b). Validity of the schizophrenia diagnosis of the
Psychiatric Assessment Schedule for Adults with Developmental Disability (PAS–ADD).
British Journal of Psychiatry, 168, 359–367.
Moss, S., Prosser, H., Ibbotson, B., & Goldberg, D. (1996c). Respondent and informant accounts
of psychiatric symptoms in a sample of patients with learning disability. Journal of
Intellectual Disability Research, 40, 457–465.
Moss, S., Ibbotson, B., Prosser, H., Goldberg, D., Patel, P., & Simpson, N. (1997). Validity of the
PAS–ADD for detecting psychiatric symptoms in adults with learning disability (mental
retardation). Social Psychiatry and Psychiatric Epidemiology, 32, 344–354.
Moss, S., Emerson, E., Kiernan, C., Turner, S., Hatton, C., & Alborz, A. (2000). Psychiatric
symptoms in adults with learning disability and challenging behaviour. British Journal of
Psychiatry, 177, 452–456.
Myrbakk, E., & von Tetzchner, S. (2008). Psychiatric disorders and behavior problems in people
with intellectual disability. Research in Developmental Disabilities, 29, 316–332.
26
Ollendick, T. H. (1983). Reliability and validity of the revised Fear Survey Schedule for Children
(FSSC–R). Behaviour Research and Therapy, 21, 685–692.
Patel, P., Goldberg, D., & Moss, S. (1993). Psychiatric morbidity in older people with moderate
and severe learning disability 2. The prevalence study. British Journal of Psychiatry, 163,
481–491.
Peduzzi, P., Concato, J., Kemper, E., Holford, T. R., & Feinstein, A. R. (1996). A simulation
study of the number of events per variable in logistic regression analysis. Journal of
Clinical Epidemiology, 49, 1373–1379.
Peoples, R., Franke, Y., Wang, Y., Perez-Jurado, L., Paperna, T., Cisco, M., & Francke, U.
(2000). A physical map, including a BAC/PAC clone contig, of the Williams-Beuren
syndrome deletion region at 7q11.23. American Journal of Human Genetics, 66, 47–68.
Porter, M. A., Coltheart, M., & Langdon, R. (2008). Theory of mind in Williams syndrome
assessed using a nonverbal task. Journal of Autism and Developmental Disorders, 38,
806–814.
Robinson, B. F., & Bakeman, R. (1998). ComKappa: A Windows '95 program for calculating
kappa and related statistics. Behavior Research Methods Instruments, & Computers, 30,
731–732.
Rougemont-Buecking, A., Rothen, S., Jeanpretre, N., Lustenberger, Y., Vandeleur, C. L.,
Ferrero, F., & Preisig, M. (2008). Inter-informant agreement on diagnoses and prevalence
estimates of anxiety disorders: Direct interview versus family history method. Psychiatry
Research, 157, 211–223.
Royal College of Psychiatrists. (2001). DC/LD: Diagnostic Criteria for Psychiatric Disorders for
Use with Adults with Learning Disabilities/Mental Retardation. London: Royal College
of Psychiatrists.
Smiley, E. (2005). Epidemiology of mental health problems in adults with learning disability: An
update. Advances in Psychiatric Treatment, 11, 214–222.
Sovner, R., & Hurley, A. D. (1983). Do the mentally retarded suffer from affective illness.
Archives of General Psychiatry, 40, 61–67.
Sparrow, S. S., Balla, D., & Cicchetti, D. (1984). Vineland Adaptive Behavior Scales–2nd
edition. Circle Pines, MN: American Guidance Service.
27
SPSS. (2006). Statistical Package for the Social Sciences (Version 15) [Computer software].
Chicago: Author.
Tsakanikos, E., Bouras, N. Sturmey, P., & Holt, G., (2006). Psychiatric co-morbidity and gender
differences in intellectual disability. Journal of Intellectual Disability Research, 50, 582–
587.
Udwin, O., Howlin, P., Davies, M., & Mannion, E. (1998). Community care for adults with
Williams syndrome: How families cope and the availability of support networks. Journal
of Intellectual Disability Research, 42, 238–245.
Udwin, O., & Yule, W. (1991). A cognitive and behavioural phenotype in Williams syndrome.
Journal of Clinical and Experimental Neuropsychology, 13, 232–244.
Udwin, O., Yule, W., & Martin, N. (1987). Cognitive abilities and behavioural characteristics of
children with idiopathic infantile hypercalcaemia. Journal of Child Psychology and
Psychiatry and Allied Disciplines, 28, 297–309.
Von Arnim, G., & Engel, P. (1964). Mental retardation related to hypercalcaemia. Developmental
Medicine and Child Neurology, 6, 366–377.
Wechsler, D. (1997). Wechsler Adult Intelligence Scale–Third Edition. San Antonio, TX,
Psychological Corp.
Whitaker, S., & Read, S. (2006). The prevalence of psychiatric disorders among people with
intellectual disabilities: An analysis of the literature. Journal of Applied Research in
Intellectual Disabilities, 19, 330–345.
Williams, L., Hastings, R. P., Noone, S. J., Burns, L., Day, J., & Mulligan, J. (2006). Life events
and psychological outcomes in adults with intellectual disabilities: Longitudinal
relationships. Paper presented at The Seattle Club Conference on Research in Intellectual
and Developmental Disabilities.
World Health Organisation. (1994). Schedules for Clinical Assessment in Psychiatry. Geneva:
Author.
28
ACKNOWLEDGEMENT
This research was generously funded by the Baily Thomas Charitable Fund and the Williams
Syndrome Foundation, which provided invaluable support in the tracing of families, and the
support of John Nelson from this foundation was of enormous benefit throughout the study.
Thanks are due to Mark Davies for his help with some of the assessments. Our sincerest thanks
go to all of the adults with Williams syndrome and their families, caregivers, supervisors, and
employers for taking part in the research and giving up so much of their time.
29
APPENDIX
Parents/Caregivers Interview: Sample Questions
Depression
Since the age of 18 years, has _____ (participant) ever had any long periods of unhappiness?
Does _____ (participant) often cry for no apparent reason?
Describe how _____ (participant) behaves during such periods.
How long do such periods of unhappiness last?
In the last 3 years, how often has _____ (participant) been depressed?
Anxiety
Is _____ (participant) overanxious? That is, does s/he have a tendency to worry or become
anxious over seemingly trivial things?
What sorts of things does _____ (participant) worry about?
Describe how _____(participant) shows such anxiety and how you cope with it.
How often does _____ (participant) become so anxious?
Fears and Phobias
Is (participant) very afraid of any particular things?
What are they?
How does _____ (participant) show their fear?
What do you do to try and help _____ (participant) cope with this?
30
Table 1. PAS-ADD Diagnoses and Agreement Types and Rates of Diagnoses and Agreement
Between Respondents and Informants
Diagnosis
Source of information
Informant onlya
n %
Respondent
onlyb
n %
Informant or
respondent
n %
Informant and
respondent
n %
Specific phobia 5 5.5 9 10.1 11 12.1 3 3.4
Depression 7 7.7 5 5.6 8 8.8 4 4.5
Agoraphobia 1 1.1 4 4.5 4 4.4 1 1.1
Panic disorder 1 1.1 3 3.4 3 3.3 1 1.1
Hypomania 3 3.3 0 0 3 3.3 0 0
Schizophrenia 1 1.1 1 1.1 2 2.2 0 0
Social phobia 0 0 2 2.2 2 2.2 0 0
Psychosis 1 1.1 1 1.1 1 1.1 1 1.1
GADc 1 1.1 1 1.1 1 1.1 1 1.1
Any anxiety 7 7.7 13 14.8 15 16.5 5 5.6
Any diagnosis 1 17.6 15 16.9 22 24.2 9 10.1
Note. From PAS-ADD (Psychiatric Assessment Schedule for Adults with Developmental
Disabilities) interviews. Percentages are based on the total sample (N = 92).
aInformation available from 91 parent/caregiver informants.
bInformation available from 89
respondents with Williams syndrome. cGeneralized anxiety disorder.
31
Table 2. PAS–ADD Diagnoses: Comorbidity
Diagnosis
Sex
Informant
Respondent
F No diagnosis Agoraphobia, specific
phobia
F No diagnosis Agoraphobia, specific
phobia
F No diagnosis Schizophrenia, panic
disorder
F Depression Specific phobia
F Depressiona Depression
a, specific
phobia
F Depressiona Depression
a, specific
phobia
F Depressiona Agoraphobia, panic
disorder, specific
phobia
F Agoraphobiaa, panic
disordera
Agoraphobiaa, panic
disordera, social phobia
F Depressiona,
generalized anxiety
disordera,
undifferentiated
psychosisa
Depressiona,
generalized anxiety
disordera,
undifferentiated
psychosisa
Note. From PAS–ADD (Psychiatric Assessment Schedule for Adults with Developmental
Disabilities).
aPAS–ADD diagnostic criteria reached on both informant and respondent interviews..
32
Table 3. Life Events Experienced Over the Preceding 2 Years
Type of event
n
% of total
sample
Deatha
Serious illness/injurya
Serious problema
Serious illness/injury (to self)
Move of residence
Break up of relationship
Something valuable lost/stolen
Unemployed/looking for work
Death (1st degree relative)
Sacked/laid off
Problems with police/authorities
Major financial crisis
Separation/divorce
Problem with drugs
Sexual problem
28
26
14
13
11
9
8
7
6
4
3
3
1
1
1
32.9
30.6
16.5
15.3
12.9
10.6
9.4
8.2
7.1
4.7
3.5
3.5
1.2
1.2
1.2
Any life event 59 69.4
No. of life events experienced
0
1
2
3
4
5
6
26
20
17
9
8
4
1
30.6
23.5
20
10.6
9.4
4.7
1.2
Median 1 –
Note. Information available from 85 parents/caregivers.
aFor example, close relative or friend.
33
Table 4. Characteristics of individuals with and without PAS–ADD diagnoses.
Characteristic
Mental health problem
Yes
n (%)
No
n (%)
Sex
Female
Male
15 (16.5)
7 (7.7)
35 (38.5)
34 (37.4)
Health problems
Yes
No
17 (19.5)
3 (3.4)
48 (55.2)
19 (21.8)
Residential status
With parents
Supported
Independently
10 (11)
10 (11)
2 (2.2)
39 (42.9)
26 (28.6)
4 (4.4)
Note. Chi-square analysis. No significant correlations were found for any variable, ps > .06.
34
Table 5. Characteristics of individuals with and without PAS–ADD diagnoses
Characteristic
Mental health problem
Yes
Mean SD (Range)
No
Mean SD Range
Agea 32 .5 9.07 -- 32.2 8.06 --
IQa
57.00 8.44 (46–80) 56.55 6.80 (45–74)
Receptive vocabularya 11.1 3.6 (5.6–17.0) 10.5 3.6 (3.2–17)
Expressive vocabularya
7.3 2.5 (3.3–12.8) 7.3 2.8 (2.8–15.5)
Adaptive Behavior Composite
Age equivalenta
Standard score
7.3 2.3 (3.7–13.8)
37.91 12.48 (19–70)
7.9 3.3 (1.8–19.0)
40.81 17.32 (19–97)
Life events 2.05 1.69 -- 1.50 1.51 --
Note. Based on ANOVA/Mann-Whitney analyses, there were no significant group differences on
any variable, p>.05.
aIn years.
bIQs are for 89 of the adults with Williams syndrome. We were unable to obtain
WAIS–III IQs for 3 participants.