www.elsevier.com/locate/schres

Schizophrenia Research

Risk factors for completed suicide in schizophrenia and other

chronic psychotic disorders: A case–control study

A. McGirr a, M. Tousignant a,b, D. Routhier b, L. Pouliot b, N. Chawky a,

H.C. Margolese c, G. Turecki a,*

a McGill Group for Suicide Studies, Douglas Hospital Research Centre, 6875 LaSalle blvd, Montreal QC, Canada H4H 1R3b University of Quebec, Montreal, Canada

c Department of Psychiatry, McGill University, Canada

Received 12 September 2005; received in revised form 20 February 2006; accepted 28 February 2006

Available online 19 April 2006

Abstract

Objective: Despite an increased risk for suicide among individuals diagnosed with psychotic disorders, risk factors for

completed suicide remain largely unexamined in this population. Using a case–control design, this study aimed to investigate

clinical and behavioural risk factors for suicide completion in schizophrenia and other chronic psychotic disorders.

Method: A total of 81 psychotic subjects were examined; of these, 45 died by suicide. Proxy-based interviews with, on average,

2 informants were conducted using the SCID I and II interviews and a series of personality trait assessments.

Results: Psychotic individuals at risk for suicide are most readily identified by the presence of depressive disorders NOS,

moderate to severe psychotic symptoms and a family history of suicidal behaviour. They also exhibited fewer negative

symptoms, had more comorbid diagnoses and, contrary to findings in other populations, we found that cluster A and C

personality trait symptoms seem to have protective effects against suicide in schizophrenics and other chronic psychotic

suicides.

Conclusions: Our study suggests that behavioural mediators of suicide risk, such as impulsive–aggressive behaviours, do not

play a role in schizophrenic and chronic psychotic suicide. This is contrary to findings in other diagnostic groups, thus implying

heterogeneity in predisposing mechanisms involved in suicide.

D 2006 Elsevier B.V. All rights reserved.

Keywords: Suicide; Schizophrenia; Alcohol abuse; Drug abuse; Personality disorders; Family history

0920-9964/$ - see front matter D 2006 Elsevier B.V. All rights reserved.

doi:10.1016/j.schres.2006.02.025

* Corresponding author. Tel.: +1 514 761 6131x2369; fax: +1 514

762 3023.

E-mail address: gustavo.turecki@mcgill.ca (G. Turecki).

1. Introduction

The importance of suicide cannot be understated as

the United States alone sees more than 30000 suicide

victims annually (Centers for Disease Control and

84 (2006) 132–143

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143 133

Prevention: Advance report of final mortality statis-

tics, 1990, 1993). Among those particularly at risk for

committing suicide are individuals suffering from

schizophrenia and other chronic psychotic disorders

(Brown, 1997; Caldwell and Gottesman, 1990) with a

level of risk approaching that of individuals suffering

from affective disorders (Caldwell and Gottesman,

1990; Plutchik et al., 1989; Westermeyer et al., 1991).

Though recent estimates are becoming more conser-

vative (Palmer et al., 2005), suicide is still the leading

cause of premature death in this population (Fenton,

2000).

Although suicidal behaviour in psychotic patients

has received a great deal of attention, examinations

of individuals diagnosed with psychotic disorders

who die by suicide are few in number. Some

clinical characteristics, such as elevated levels of

depressive symptoms or the presence of depressive

disorders (Altamura et al., 2003; Fenton, 2000;

Hawton et al., 2005; Heila et al., 1997; Hu et al.,

1991; Kelly et al., 2004; Kreyenbuhl et al., 2002;

Kuo et al., 2005; Plutchik et al., 1989; Potkin et

al., 2003; Sinclair et al., 2004), have consistently

been associated with suicide and suicidal behaviour

among psychotic individuals, whereas others, such

as alcohol and substance abuse (Baca-Garcia et al.,

2005; Gut-Fayand et al., 2001; Kreyenbuhl et al.,

2002; Kuo et al., 2005; Sinclair et al., 2004) have

been associated with suicide attempts but not

completed suicide. Mixed findings have emerged

in studies of positive and negative symptoms

(Fenton, 2000; Hu et al., 1991; Kelly et al.,

2004; King et al., 2001; Sinclair et al., 2004).

Though an increased frequency of an active illness

phase among schizophrenic suicides has been

reported (Heila et al., 1997), and these individuals

are also more likely to have experienced psychotic

symptoms in the month preceding their suicides

(Hu et al., 1991), the association between the

severity of current psychotic symptoms and com-

pleted suicide has, to our knowledge, not been

examined in schizophrenia and other chronic

psychotic disorders. Recently, researchers have

begun to examine factors such as comorbidity

among this population (Kuo et al., 2005); additional

studies, however, are needed to confirm and better

characterize comorbidity patterns among psychotic

suicides. At the same time, structured information

on important clinical risk factors, such as person-

ality disorders, is, to our knowledge, absent from

the literature on suicide in schizophrenia and in

other chronic psychotic disorders.

Similarly, although there has been growing

evidence supporting the role of impulsive and

aggressive behaviours in suicide risk among unse-

lected suicides or in clinical subgroups, such as

those suicides whose primary psychiatric condition

was a major depressive disorder (Dumais et al.,

2005a), for the most part, data on impulsive and

aggressive behaviours in suicide completers are

limited and primarily based on indirect evidence

such as the prevalence of diagnostic categories

associated with aggressive and impulsive traits

(Brent, 1995; Cheng et al., 1997). Impulsive and

aggressive behaviours have, to our knowledge, not

been properly examined in psychotic completed

suicide and it remains unclear whether they mediate

suicide risk among psychotic individuals, as they

are believed to in other populations (Dumais et al.,

2005a).

The goal of the current study was to address the

lacunae and re-examine areas in which inconsistent

findings have emerged concerning the risk for

completed suicide in a sample of suicide victims

and matched living controls diagnosed with psy-

chotic disorders. More specifically, our primary

hypothesis was that concomitant psychopathology,

notably depression and psychopathology associated

with impulse discontrol (i.e. substance abuse dis-

orders and cluster B personality disorders), and

impulsive aggressive behaviours would be associ-

ated with completed suicide among psychotic

individuals. At the same time, we hypothesized

that the severity of psychotic symptoms would be

associated with completed suicide among this

population.

2. Methods

2.1. Subjects

Our sample consisted of 81 (62 male and 19

female) Caucasian subjects who were diagnosed with

schizophrenia or a chronic psychotic disorder. This

sample included 45 suicide completers and 36

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143134

matched controls. The mean age of the suicide group

was 34.45F11.61 years and 34.95F9.17 years for

the control group (t(79)= .197, p= .832). Diagnostic

distribution was similar (v2=4.284, df =4, p =.369)between groups: schizophrenia (86.0% vs. 83.8%),

schizoaffective disorder (7.0% vs. 13.5%), as well as

delusional disorder or psychotic disorder NOS (2.7%

vs. 12.5%). Moreover, no differences were observed

between groups in the proportion of schizophrenia

subtypes (v2=5.657, df =3, p =.130) nor in history

of hospitalization (3.18F3.68 vs. 5.31F8.27,

t(73)=1.457, p =.149). Suicide cases were recruited

during a period of approximately four years through an

ongoing collaboration with the Quebec Coroner’s

Office and the Montreal Central Morgue and cases

diagnosed with a psychotic disorder were identified

with help from the Quebec Statistics Institute and the

RAMQ, the Quebec Health Board. Methods of suicide

included hanging (51.2%), jumping (11.6%), stabbing

or laceration (11.6%), drowning (7.0%) and other

(19.4%).

The control group was recruited among psychiatric

outpatients, from psychiatric community clinics affil-

iated with McGill University and the University of

Montreal. This study was approved by our local IRB

and suicide families, controls and informants signed

written informed consents.

2.2. Measures

A psychological autopsy method was used to

diagnose axis I and II DSM-IV psychiatric disorders,

personality, impulsivity, hostility and lifetime history

of aggression. This validated technique (Conner et al.,

2001a; Kelly and Mann, 1996; Zhang et al., 2003)

involves selecting the family member or friend best

acquainted with the subject to serve as an informant.

To ensure the comparability among cases and

controls, controls named an informant for the inter-

view process. Informants included mother (47.4% vs.

54.8%), father (13.2% vs. 6.5%), sibling (34.2% vs.

16.1%), child (2.6% vs. 6.5%) and significant other

(2.6% vs. 16.1%). We have previously reported that

the rate of specific disorders identified does not differ

between informants for a given subject (Dumais et al.,

2005a), nor does it vary as a function of the

informant’s relationship with the subject (Lesage et

al., 1994).

Psychiatric diagnoses were obtained using the

SCID-I (First et al., 2001) and SCID-II (First et al.,

1995) interviews. The severity of psychotic symp-

toms was determined using a section of the SCID-I

assessing functional impairment due to psychotic

symptoms. The assessment of axis II pathology

among psychotic individuals poses a unique chal-

lenge, for its presence must be established before the

onset of the disorder. Therefore, symptoms were

deemed present only if informants confirmed their

presence prior to the onset of psychotic symptoms;

this was further reviewed by a panel of psychiatrists

and psychologists (GT, NC and AM, who had

previous experience with the instrument). For a

subset of the current sample, agreement between

subject and informant was calculated: .77 depressive

disorder NOS; 1.0 substance abuse/dependence; 1.0,

schizophrenia and schizoaffective; 1.0, cluster A

personality disorders; 1.0 cluster B personality dis-

orders and .77, cluster C personality disorders. For a

different subset, two or more interviewers were asked

to separately rate the same subject; inter-rater

agreement was calculated: .72, depressive disorder

NOS; .77, substance abuse/dependence; .88, schizo-

phrenia and schizoaffective; 1.0, cluster A personality

disorders; 1.0 cluster B personality disorders and 1.0,

cluster C personality disorders.

Behavioural measures assessed in this study

focused on those commonly regarded as risk factors

for suicide, notably, personality traits and measures

of impulsive–aggressive behaviours. The Brown–

Goodwin History of Aggression (BGHA) (Brown

and Goodwin, 1986) is an 11-item assessment of

lifetime aggressive behaviours across childhood,

adolescence and adulthood. The Barratt Impulsive-

ness Scale (BIS-11) (Barratt, 1965) consists of 30

items and has been commonly used in the investi-

gation of impulsive behaviours. The Buss–Durkee

Hostility Inventory (BDHI) (Buss and Durkee, 1957)

is a 75-item assessment of impulsive aggression.

Last, the Trait and Character Inventory (TCI)

(Cloninger et al., 1994) was used to complete

information by assessing 4 basic temperament and

3 character dimensions. Consistent with our previous

studies in different clinical samples (Dumais et al.,

2005a,b) and with studies by other groups (Conner

et al., 2001a; Zhang et al., 2003), the internal

consistency estimates in this study were overall

Table 1

Pearson’s correlations for BIS, BGLHA, BDHI and TCI subscales

P RD HA NS ST SD C BDHI BGLHA BIS

BIS .145 .018 � .068 � .008 � .042 � .276* � .002 .244 .412* �BGLHA � .133 .081 � .075 � .109 � .150 � .208 � .109 .315* –

BDHI � .183 � .056 � .165 � .357** � .197 � .474** � .241 –

C .258** .312* .281* .400** .550** .587** –

SD .449** .513** .473** .626** .649** –

ST .472** .451** .438** .402** –

NS .533** .530*** .463** –

HA .376** .432** –

RD .388** –

P –

BIS: Barratt Impulsivity Scale. BGLHA: Brown–Goodwin Lifetime History of Aggression. BDHI: Buss–Durkee Hostility Inventory. TCI:

Temperament and Character Inventory. C: TCI Cooperativeness subscale. SD: TCI Self-directedness subscale. ST: TCI Self-transcendence

subscale. NS: TCI Novelty seeking subscale. HA: TCI Harm avoidance subscale. RD: Reward dependence subscale. P: TCI Persistence

subscale.

* p V .05.** p V .01.*** p V .001.

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143 135

excellent with the informant version for the BGHA

(a =.84), the BIS (a= .90), the BDHI (a =.84), andthe TCI (a =.90). In addition, concurrent and con-

Table 2

Sociodemographic information and family history

Risk factor Suicides Controls Ana

% % v2

Gender .6

Male 36 (80.0) 26 (72.2)

Female 9 (20.0) 10 (27.8)

Marital status 6.2

Single 31 (75.6) 17 (48.6)

Dating 1 (2.4) 1 (2.9)

Married 3 (7.3) 7 (20.0)

Separated/divorced 6 (14.6) 10 (28.6)

Highest education 2.8

Primary 5 (12.2) 5 (14.3)

Secondary 18 (43.9) 10 (28.6)

Some university 12 (29.3) 16 (45.7)

Bachelor’s or higher 6 (14.6) 4 (11.4)

Household income 2.2

b$10000 10 (47.6) 15 (44.1)

$10000b$20000 4 (19.0) 5 (14.7)

$20000b$40000 3 (14.3) 6 (17.6)

$40000b$60000 2 (9.5) 7 (20.6)

z$60000 2 (9.5) 1 (2.9)

Living alone or not 15 (33.3) 8 (22.2) .3

Family history

Suicidal behaviour 17 (54.8) 4 (12.9) 12.1

Psychopathology 24 (92.3) 25 (83.3) 1.0

Psychopathology includes depression, mania, schizophrenia, alcoholism, d

vergent validity estimates of proxy-based behaviou-

ral measures indicate excellent levels of association

(Table 1).

lyses

df p OR 95% CI

74 1 .412 .650 .232–1.825

49 3 .100

01 3 .423

77 4 .685

45 1 .557 1.406 .450–4.391

70 1 .000 8.196 2.311–29.073

26 1 .311 2.400 .424–13.576

rug abuse and obsessive compulsive disorder.

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143136

2.3. Statistical analyses

Statistical analyses were performed using the SPSS

statistical package version 11.5 (SPSS Inc., Chicago,

IL). Chi-square analysis, and odds ratio (with exact

Table 3

Comparisons of potential risk factors for suicide among individuals diagn

Risk factor Suicides Controls An

N (%) N (%) v2

Illness characteristics

Current moderate or severe

psychotic symptoms

17 (68.0) 8 (23.5) 11.

Current axis I

Depressive disorder NOS 9 (20.9) 1 (2.8) 5.

Substance abuse disorder 11 (27.5) 6 (17.1) 1.

Alcohol 6 (14.0) 3 (8.6) .

Drug 10 (25.0) 4 (11.1) 2.

Lifetime axis I

Depressive disorder NOS 9 (21.4) 7 (19.4) .

Substance abuse disorder 14 (36.8) 17 (50.0) 1.

Alcohol 9 (20.9) 7 (20.6) .

Drug 11 (28.9) 14 (40.0) .

Mean SD Me

Illness characteristics

Age of onset 21.97 5.50 23.

Negative symptoms .71 .88 1.

Positive symptoms 5.49 2.91 6.

Axis I

Current comorbid disorders 1.64 .90 1.

Lifetime comorbid disorders 1.93 1.16 1.

Axis II symptoms

Cluster A 1.34 2.09 2.

Cluster B 1.95 2.45 2.

Cluster C 1.87 1.96 3.

Behavioural measures

BIS 65.27 15.01 70.

BGLHA 9.85 9.23 13.

BDHI 33.90 13.98 34.

Temperament and character

Self-directedness 36.09 7.27 34.

Cooperativeness 41.08 3.67 41.

Self-transcendence 48.30 8.23 49.

Novelty seeking 37.08 4.87 37.

Harm avoidance 33.58 3.73 37.

Reward dependence 22.64 2.45 22.

Persistence 9.39 1.42 9.

limit test to evaluate the 95% confidence interval)

were used to compare categorical variables and the

Student’s t-test was used in the analysis of continuous

variables. The joint effect of the independent variables

was then analyzed by stepwise logistic regression and

osed with psychotic disorders

alyses

df p OR 95% CI

668 1 .001 6.906 2.176–21.921

840 1 .016 9.265 1.113–77.124

142 1 .285 1.833 .598–5.619

548 1 .459 1.730 .400–7.481

432 1 .119 2.667 .755–9.420

047 1 .829 1.130 .374–3.417

267 1 .260 .583 .228–1.496

001 1 .971 1.021 .337–3.096

988 1 .320 .611 .231–1.619

an SD t df p

57 8.54 � .843 53 .403

21 1.14 2.109 75 .039

29 2.37 1.307 74 .193

20 .40 �2.690 78 .009

94 .92 .053 78 .957

41 2.23 2.140 73 .037

50 2.88 .384 73 .384

41 2.92 2.704 73 .009

58 13.18 1.511 65 .129

17 10.57 1.390 67 .170

81 12.36 .279 68 .781

64 5.00 .914 65 .364

83 3.94 � .798 65 .428

48 6.69 � .628 65 .518

75 3.76 � .633 65 .529

75 3.76 � .784 65 .436

56 2.35 .138 65 .891

52 1.40 � .354 65 .725

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143 137

correlation matrix with suicide status as the dependent

variable.

3. Results

Sociodemographic characteristics of the sample

including family history are shown in Table 2. An

increased risk for suicide was associated with a family

history of suicidal behaviour (OR=8.19; 95% CI:

2.31–29.07); however, this was not conditional on an

increased family history of psychopathology, defined

as the presence of depression, mania, schizophrenia,

alcoholism, drug abuse, or obsessive compulsive

disorder (v2=1.02, df =1, p =.311). Further, those

with a family history of suicidal behaviour did not

differ from those without as relates to impulsivity

and aggression (BIS: 68.25F24.81 vs. 68.21F12.90,

t(43)=� .005, p = .996; BGLHA: 11.13F5.13 vs.

13.19F11.08, t(43)= .511, p =.430).

Table 3 addresses comparisons between psychotic

suicides and psychotic controls diagnosed with respect

to axis I and II characteristics, as well as behavioural,

character and temperament measures. Psychotic sui-

cide victims were more likely to have currently (last 6

months) met the criteria for a depressive disorder NOS

(OR=5.03; 95% CI: 1.08–26.02) and to have had two

Fig. 1. Predictors

or more comorbid axis I disorders (OR=3.39; 95 %CI:

1.22–9.40). Psychotic suicides were also more likely

to have been currently experiencing moderate to

severe psychotic symptoms (OR=6.90; 95% CI:

2.17–21.92) and to have exhibited lower levels of

negative symptoms (OR=.648; 95% CI: .26–1.60).

With respect to axis II diagnoses and symptoms,

psychotic suicides were characterized by lower levels

of cluster A symptoms (1.34F2.09 vs. 2.41F2.23,

t(73)=2.14, p b .05) and cluster C symptoms (1.87F1.96 vs. 3.41F2.92, t(73)=2.70, p b .01). No signif-

icant differences were found for any other axis I

disorders, cluster B symptoms, behavioural or temper-

ament and character measures.

3.1. Predictors of suicide

To determine which variables independently con-

ferred an increased risk for suicide, a stepwise logistic

regression with correlation matrix was conducted. The

model included the predictors psychotic symptom

severity, negative symptoms, current depressive dis-

order NOS, current comorbidity, cluster A symptoms,

cluster C symptoms and family history of suicidal

behaviour while suicide status served as the dependent

variable. Final estimates are reported in Fig. 1. The

model indicated that moderate to severe current

of suicide.

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143138

psychotic symptoms (adjusted OR=87.37; 95% CI:

3.30–2309.72), current depressive disorder NOS

(adjusted OR=395.02; 95% CI: 1.47–106 140.5),

and cluster C symptoms (adjusted OR=.25; 95% CI:

.07–.91) were independent predictors of suicide, while

a trend towards significance was observed for a family

history of suicidal behaviour (adjusted OR=16.37;

95% CI: .66–403.06).

4. Discussion

In this study, 45 suicide victims diagnosed with

schizophrenia and other chronic psychotic disorders

were compared with 36 clinically similar controls. As

individuals diagnosed with psychotic disorders are at

an increased risk for suicide (Black et al., 1985;

Brown, 1997; Caldwell and Gottesman, 1990; Heila et

al., 1997; Henriksson et al., 1993), it is essential to

determine whether predictors of suicide among

psychotic individuals are similar to those recognized

to play a role in other clinical populations, such as

among patients with major depressive disorder. Few

studies on psychotic suicide completers have investi-

gated risk factors using a psychological autopsy with

a case–control design and standardized interviews to

retrieve information. Further, to our knowledge this is

the first study among this population to have

examined the relationship between completed suicide

and the potential risk factors a) impulsive aggressive

behaviours, b) personality disorders, and c) the current

severity of psychotic symptoms.

4.1. Illness characteristics

In this sample, suicide victims weremore likely than

controls to have experienced moderate to severe

psychotic symptoms at the time of suicide and suicide

completers exhibited fewer negative symptoms. A

logistic regression showed that greater psychotic

symptom severity was a good predictor of suicide with

an adjusted risk of 87.37, whereas negative symptoms

did not independently predict suicide. With respect to

current psychotic symptom severity, our findings are an

extension of previous findings that a large proportion of

schizophrenic suicides are in the active phase of the

illness (Heila et al., 1997) and that schizophrenic

suicides are more likely to experience psychotic

symptoms in the month preceding their suicides than

psychotic controls (Hu et al., 1991). A recent meta-

analysis has revealed an increased risk for suicide to be

associated with poor treatment compliance (Hawton et

al., 2005). Future studies should investigate the

independence with which current treatment compli-

ance and functional impairment due to psychotic

symptoms increase psychotic individuals’ risk for

suicide. The protective nature of negative symptoms

is in line with Fenton’s (Fenton, 2000; Fenton and

McGlashan, 1994; Fenton et al., 1997) deficit syn-

drome, a subtype of schizophrenia characterized by

insidious onset, the presence of negative symptoms at

onset, the progressing severity of negative symptoms

and a high probability of lifelong disability.

4.2. Axis I characteristics and behavioural measures

In line with previous findings of an increased risk

for suicide among schizophrenic and other psychotic

individuals associated with depressive disorders or

elevated levels of depressive symptoms (Altamura et

al., 2003; Cheng et al., 2000; Fenton, 2000; Foster et

al., 1997; Haw et al., 2002; Hawton et al., 2005;

Henriksson et al., 1993; Hu et al., 1991; Kelly et al.,

2004; Kreyenbuhl et al., 2002; Kuo et al., 2005;

Lesage et al., 1994; Mann et al., 2000; Plutchik et al.,

1989; Potkin et al., 2003; Roy, 1982; Rudd et al.,

1993; Shafii et al., 1988; Statham et al., 1998; Vieta et

al., 1992), we found an association between complet-

ed suicide and the presence of comorbid depressive

episodes. Further, a logistic regression revealed that

current depressive disorder NOS was the independent

predictor of suicide with the largest adjusted effect on

risk.

Consistent with previous reports (Kuo et al., 2005;

Sinclair et al., 2004), we did not find a significant

association between completed suicide and substance

abuse among schizophrenics and other chronic psy-

chotic individuals. Some studies, however, have

found such an association with suicide attempts in

this population (Altamura et al., 2003; Gut-Fayand et

al., 2001; Potkin et al., 2003) and consistent support

for the association between suicide risk and substance

abuse disorders has been reported in other clinical

populations (Brent et al., 2002; Castle et al., 2004;

Cheng et al., 2000; Hawton et al., 2003; King et al.,

2001; Lesage et al., 1994; Malone et al., 1995; Mann

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143 139

et al., 1999; Shafii et al., 1988; Statham et al., 1998).

Substance abuse appears to be a characteristic

frequently associated with psychotic illnesses and,

by nature of the design used, once we controlled for

the primary psychopathological condition, no effect of

substance-related disorders was observed on suicide

risk. A recent meta-analysis has reported that drug

abuse, but not alcohol abuse disorders, are associated

with an increased risk for suicide among schizo-

phrenics (Hawton et al., 2005). In line with these

findings, psychotic suicides and controls showed

different levels of current drug abuse (25.0% vs.

11.1%), yet this difference did not reach significance.

We did not find an association between impulsive

and aggressive behaviours and schizophrenia as well

as other chronic psychotic suicides. This is, to our

knowledge, the first study to have examined impul-

sive and aggressive behaviours using proxy-based

behavioural measures in this population. With respect

to aggression, our findings confirm previous studies

having used other means of assessing aggression

(Fenton, 2000; Sinclair et al., 2004). In the case of

impulsivity, other studies have found an association

between impulsivity and risk for suicide and suicidal

behaviour among schizophrenics, however they have

done so using indirect means by a) finding that

schizophrenic substance abusers are more impulsive

and assuming that, as in other populations, substance

abusers are more likely to attempt suicide (Gut-

Fayand et al., 2001), showing b) that a smaller

proportion of schizophrenic suicides appear to plan

their suicides (Kreyenbuhl et al., 2002), and c) that

such individuals had previously attempted suicide or

had been promiscuous (Fenton, 2000). This is, to our

knowledge, the first study to examine impulsivity

using a behavioural measure among psychotic suicide

completers, higher scores on which did not charac-

terize suicide completers. If confirmed in future

studies, these findings suggest that suicide risk may

be mediated differently across the major psychopath-

ological categories and provide further support for the

presence of heterogeneity in predisposing mecha-

nisms whereby suicide risk is increased in different

populations.

As it has been consistently reported among other

populations (Beautrais et al., 1996; Hawton et al.,

2003; Henriksson et al., 1993; Lesage et al., 1994;

Marttunen et al., 1991; Muller et al., 2005; Rudd et

al., 1993), and more recently, by Kuo et al. (Kuo et al.,

2005) among psychotic suicides, a significant rela-

tionship emerged between current comorbid axis I

disorders and psychotic completed suicide. In the

current sample, comorbidity appears to have been

driven by comorbid diagnoses of depressive disorder

NOS. Unlike reports in other diagnostic groups,

however, no excess lifetime comorbidity was ob-

served and the level of current comorbidity is of a

lesser magnitude than that reported among other

populations at risk for suicide (Kim et al., 2003).

This may be due to the lack of excess of levels of

impulsive–aggressive behaviours among the psychot-

ic suicides, as the comorbidity reported among

unselected suicides is primarily related to the con-

comitant presence of disorders that are related to

impulse discontrol, including substance abuse disor-

ders and cluster B personality disorders (Kim et al.,

2003).

4.3. Family history

We found an increased risk for suicide among

individuals with schizophrenia and chronic psychotic

disorders who had a family history of suicidal

behaviour. Moreover, our analyses indicated that this

increased risk operated independently from psycho-

pathology. Although these findings may be due to

possible artifacts such as a heightened awareness

about a family history of suicidal behaviour following

a suicide of a close family member, our findings are in

line with a large body of evidence coming from

studies using different methodologies supporting

familial aggregation of suicidal behaviour. For exam-

ple, in other diagnostic populations support for

familial clustering of suicide has been obtained (Roy

et al., 1991, 1995; Statham et al., 1998) and it has also

been reported that familial aggregation of suicidal

behaviour operates independently from psychopathol-

ogy (Brent et al., 1996; Cheng et al., 2000; Johnson et

al., 1998; Kim et al., 2005; Statham et al., 1998). In

previous studies it has been suggested that impulsive–

aggressive behaviours could mediate familial trans-

mission of suicidal behaviour (Brent et al., 1996,

2002, 2004; Brent and Mann, 2005; Kim et al., 2005),

however, in the current sample, measures of impulsive

aggression were not associated with family histories

of suicidal behaviour. Given that we were unable to

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143140

observe an association between suicide risk, impul-

sive–aggressive behaviours and their related psycho-

pathological conditions, it remains to be determined

what, if any, mechanisms at the behavioural level

could mediate familial transmission of suicide differ-

entiating those with chronic psychotic conditions and

other populations.

4.4. Personality disorders

Our psychotic suicides were less likely to have

cluster A and C symptoms. While the role of

personality disorders in suicide risk has been exten-

sively investigated in unselected suicide completers

and suicide attempters (Apter et al., 1991; Beautrais et

al., 1996; Brent et al., 2002; Cheng et al., 2000, 1997;

Foster et al., 1997; Haw et al., 2001; Henriksson et al.,

1993; Lesage et al., 1994; Malone et al., 1995; Mann

et al., 1999; Shearer et al., 1988; Soloff et al., 1994),

the relationship between personality traits, personality

disorders and suicide risk has not yet been examined

in schizophrenic or psychotic suicides. Certainly, the

investigation of personality traits and disorders in

patients with schizophrenia and similar conditions is

potentially confounded by the natural course of

psychotic disorders and methodological difficulties

intrinsic to the retrospective investigation of premor-

bid personality traits in this diagnostic group. Never-

theless, our personality trait measures showed very

good reliability and good to excellent concurrent and

convergent validity, suggesting that personality meas-

ures in our sample are precise and accurate. Our

findings are in stark contrast with those from

examinations of personality variants in unselected

suicides, where personality disorders have emerged as

important risk factors for completed suicide (Apter et

al., 1991; Beautrais et al., 1996; Brent et al., 2002;

Cheng et al., 2000, 1997; Foster et al., 1997; Haw et

al., 2001; Henriksson et al., 1993; Lesage et al., 1994;

Malone et al., 1995; Mann et al., 1999; Shearer et al.,

1988; Soloff et al., 1994). Though further examina-

tions of personality disorders among individuals

diagnosed with psychotic disorders are needed, the

greater prevalence of cluster A and C symptoms

among controls has interesting implications. First,

higher cluster A symptoms are consistent with

negative symptom differences and hypothesized pre-

morbid psychotic features (Fenton, 2000; Fenton and

McGlashan, 1994; Fenton et al., 1997). Second,

cluster C symptoms may be associated with lower

social functioning, less exposure and thus lower levels

of interpersonal conflict or negative life event

occurrence. Last, lower levels of cluster A symptoms

may be associated with risk factors specific to suicide

among those suffering from psychotic disorders that

were not assessed, such as greater illness insight

(Schwartz and Smith, 2004) or fear of mental

disintegration (Hawton et al., 2005). These possibil-

ities require further investigation.

4.5. Limitations

In this study we opted for living controls of

comparable psychopathology and sociodemographic

characteristics and assessments using proxy-based

procedures. While controlling for the presence of

major psychopathology and using similar methods in

both groups helps avoid several methodological

shortcomings, our study has, nevertheless, limitations

that are inherent to post-mortem studies involving

proxy-based interviews. Informants may have imper-

fect and varying levels of information about the

subject from which the subject’s state of mind is

reconstructed. However, by using proxy-based inter-

views for both cases and controls, this possible bias

was controlled for. In addition, similar to studies

carried out by other groups (Conner et al., 2001a,b),

and in our studies of suicide in different diagnostic

subgroups (Dumais et al., 2005a,b), our instruments

had good concordance rates between proxy-based and

directly obtained information. Nonetheless, when

comparing suicides to living controls, it is important

to consider that family members in grief may

exaggerate or overemphasize symptoms and signs in

the deceased and that an asymmetry of information

may exist between the proxies of suicide completers

and living subjects. Other limitations of this study are

related to the relatively small sample, which is a

consequence of the low frequency of chronic psy-

chotic subjects (c7%) among unselected suicides.

Similarly, living controls may possess latent risk for

suicide, yet this is unlikely due to a lifetime risk of 5%

among psychotic individuals, decreasing risk with

time following illness onset and a window of risk

primarily limited to the first ten years following illness

onset. Should controls possess latent risk, this would

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143 141

result in reduced power and would not be likely to

influence our positive findings. Nevertheless, addi-

tional investigations among larger samples may be

required to identify differential risk for suicide

associated with risk factors such as drug abuse.

4.6. Conclusion

Our study suggests that behavioural mediators of

suicide risk, such as impulsive–aggressive behaviours

do not play a role in schizophrenic and chronic

psychotic suicide, contrary to findings in other clinical

populations. This implies heterogeneity in predispos-

ing mechanism involved in suicide, a possibility that

future studies should pursue both between and within

specific populations. We also found that cluster A and

C personality traits appear to have a protective effect

against suicide in schizophrenics and other chronic

psychoses, though further research is needed to

elucidate the interaction between personality, psychot-

ic disorders and suicide. The clinical implications of

our findings are important, as psychotic individuals at

risk for suicide are most readily identified by the

presence of depressive disorders NOS, moderate to

severe psychotic symptoms and a family history of

suicidal behaviour. Clinicians may also include an

illness profile including lower levels of negative

symptoms to further refine their identification of

individuals at risk for completed suicide.

References

Altamura, A.C., Bassetti, R., Bignotti, S., Pioli, R., Mundo, E.,

2003. Clinical variables related to suicide attempts in

schizophrenic patients: a retrospective study. Schizophr. Res.

60, 47–55.

Apter, A., Kotler, M., Sevy, S., Plutchik, R., Brown, S.L., Foster,

H., Hillbrand, M., Korn, M.L., van Praag, H.M., 1991.

Correlates of risk of suicide in violent and nonviolent

psychiatric patients. Am. J. Psychiatry 148, 883–887.

Baca-Garcia, E., Perez-Rodriguez, M.M., Diaz Sastre, C., Saiz-

Ruiz, J., de Leon, J., 2005. Suicidal behavior in schizophrenia

and depression: a comparison. Schizophr. Res. 75, 77–81.

Barratt, E.S., 1965. Factor analysis of some psychometric measures

of impulsiveness and anxiety. Psychol. Rep. 16, 547–554.

Beautrais, A.L., Joyce, P.R., Mulder, R.T., Fergusson, D.M.,

Deavoll, B.J., Nightingale, S.K., 1996. Prevalence and comor-

bidity of mental disorders in persons making serious

suicide attempts: a case–control study. Am. J. Psychiatry 153,

1009–1014.

Black, D.W., Warrack, G., Winokur, G., 1985. Excess mortality

among psychiatric patients. The Iowa Record–Linkage Study.

Jama 253, 58–61.

Brent, D.A., 1995. Risk factors for adolescent suicide and suicidal

behavior: mental and substance abuse disorders, family envi-

ronmental factors, and life stress. Suicide Life-Threat. Behav. 25

Suppl, 52–63.

Brent, D.A., Mann, J.J., 2005. Family genetic studies, suicide, and

suicidal behavior. Am. J. Med. Genet. C Semin. Med. Genet.

133, 13–24.

Brent, D.A., Bridge, J., Johnson, B.A., Connolly, J., 1996. Suicidal

behavior runs in families. A controlled family study

of adolescent suicide victims. Arch. Gen. Psychiatry 53,

1145–1152.

Brent, D.A., Oquendo, M., Birmaher, B., Greenhill, L., Kolko, D.,

Stanley, B., Zelazny, J., Brodsky, B., Bridge, J., Ellis, S.,

Salazar, J.O., Mann, J.J., 2002. Familial pathways to early-

onset suicide attempt: risk for suicidal behavior in offspring of

mood-disordered suicide attempters. Arch. Gen. Psychiatry 59,

801–807.

Brent, D.A., Oquendo, M., Birmaher, B., Greenhill, L., Kolko, D.,

Stanley, B., Zelazny, J., Brodsky, B., Melhem, N., Ellis, S.P.,

Mann, J.J., 2004. Familial transmission of mood disorders:

convergence and divergence with transmission of suicidal

behavior. J. Am. Acad. Child Adolesc. Psych. 43, 1259–1266.

Brown, S., 1997. Excess mortality of schizophrenia. A meta-

analysis. Br. J. Psychiatry 171, 502–508.

Brown, G.L., Goodwin, F.K., 1986. Human aggression and suicide.

Suicide Life-Threat. Behav. 16, 223–243.

Buss, A.H., Durkee, A., 1957. An inventory for assessing different

kinds of hostility. J. Consult. Psychol. 21, 343–349.

Caldwell, C.B., Gottesman, I.I., 1990. Schizophrenics kill them-

selves too: a review of risk factors for suicide. Schizophr. Bull.

16, 571–589.

Castle, K., Duberstein, P.R., Meldrum, S., Conner, K.R., Conwell,

Y., 2004. Risk factors for suicide in blacks and whites: an

analysis of data from the 1993 National Mortality Followback

Survey. Am. J. Psychiatry 161, 452–458.

Centers for Disease Control and Prevention: Advance report of final

mortality statistics, 1990, 1993, in Monthly Vital Statistics

Report, 41, pp. 1–52.

Cheng, A.T., Mann, A.H., Chan, K.A., 1997. Personality

disorder and suicide. A case–control study. Br. J. Psychiatry

170, 441–446.

Cheng, A.T., Chen, T.H., Chen, C.C., Jenkins, R., 2000.

Psychosocial and psychiatric risk factors for suicide. Case–

control psychological autopsy study. Br. J. Psychiatry 177,

360–365.

Cloninger, C.R., Przybeckm, T.R., Svrakic, D.M., Wetzel, R.D.,

1994. The Temperament and Character Inventory (TCI): A

Guide to Its Development and Use. Center for Psychobiology of

Personality, St-Louis, Missouri.

Conner, K.R., Conwell, Y., Duberstein, P.R., 2001. The validity of

proxy-based data in suicide research: a study of patients 50

years of age and older who attempted suicide. II. Life events,

social support and suicidal behavior. Acta Psychiatr. Scand. 104,

452–457.

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143142

Conner, K.R., Cox, C., Duberstein, P.R., Tian, L., Nisbet, P.A.,

Conwell, Y., 2001. Violence, alcohol, and completed suicide: a

case–control study. Am. J. Psychiatry 158, 1701–1705.

Dumais, A., Lesage, A.D., Alda, M., Rouleau, G., Dumont, M.,

Chawky, N., Roy, M., Mann, J.J., Benkelfat, C., Turecki, G.,

2005a. Risk factors for suicide completion in major depression:

a case–control study of impulsive and aggressive behaviors in

men. Am. J. Psychiatry 162, 2116–2124.

Dumais, A., Lesage, A.D., Lalovic, A., Seguin, M., Tousignant, M.,

Chawky, N., Turecki, G., 2005b. Is violent method of suicide a

behavioral marker of lifetime aggression? Am. J. Psychiatry

162, 1375–1378.

Fenton, W.S., 2000. Depression, suicide, and suicide prevention in

schizophrenia. Suicide Life-Threat. Behav. 30, 34–49.

Fenton, W.S., McGlashan, T.H., 1994. Antecedents, symptom

progression, and long-term outcome of the deficit syndrome in

schizophrenia. Am. J. Psychiatry 151, 351–356.

Fenton, W.S., McGlashan, T.H., Victor, B.J., Blyler, C.R., 1997.

Symptoms, subtype, and suicidality in patients with schizophre-

nia spectrum disorders. Am. J. Psychiatry 154, 199–204.

First, M.B., Spitzer, R.L., Gibbon, M., Williams, J.B.W., Lorna,

B., 1995. Structure Clinical Interview for DSM-IV Axis II

Personality Disorders (SCID-II). Biometrics Research Depart-

ment, New York State Psychiatric Institute, New York.

First, M.B., Gibbon, M., Spitzer, R.L., Williams, J.B.W., 2001.

Structured Clinical Interview for DSM-IV-TR Axis I Disorders,

Research Version, Patient Edition with Psychotic Screen.

Biometrics Research, New York State Psychiatric Institute,

New York.

Foster, T., Gillespie, K., McClelland, R., 1997. Mental disorders and

suicide in Northern Ireland. Br. J. Psychiatry 170, 447–452.

Gut-Fayand, A., Dervaux, A., Olie, J.P., Loo, H., Poirier, M.F.,

Krebs, M.O., 2001. Substance abuse and suicidality in

schizophrenia: a common risk factor linked to impulsivity.

Psychiatry Res. 102, 65–72.

Haw, C., Hawton, K., Houston, K., Townsend, E., 2001. Psychiatric

and personality disorders in deliberate self-harm patients. Br. J.

Psychiatry 178, 48–54.

Haw, C., Houston, K., Townsend, E., Hawton, K., 2002. Deliberate

self harm patients with depressive disorders: treatment and

outcome. J. Affect. Disord. 70, 57–65.

Hawton, K., Houston, K., Haw, C., Townsend, E., Harriss, L., 2003.

Comorbidity of axis I and axis II disorders in patients who

attempted suicide. Am. J. Psychiatry 160, 1494–1500.

Hawton, K., Sutton, L., Haw, C., Sinclair, J., Deeks, J.J., 2005.

Schizophrenia and suicide: systematic review of risk factors. Br.

J. Psychiatry 187, 9–20.

Heila, H., Isometsa, E.T., Henriksson, M.M., Heikkinen, M.E.,

Marttunen, M.J., Lonnqvist, J.K., 1997. Suicide and schizo-

phrenia: a nationwide psychological autopsy study on age- and

sex-specific clinical characteristics of 92 suicide victims with

schizophrenia. Am. J. Psychiatry 154, 1235–1242.

Henriksson, M.M., Aro, H.M., Marttunen, M.J., Heikkinen, M.E.,

Isometsa, E.T., Kuoppasalmi, K.I., Lonnqvist, J.K., 1993.

Mental disorders and comorbidity in suicide. Am. J. Psychiatry

150, 935–940.

Hu, W.H., Sun, C.M., Lee, C.T., Peng, S.L., Lin, S.K., Shen, W.W.,

1991. A clinical study of schizophrenic suicides. 42 cases in

Taiwan. Schizophr. Res. 5, 43–50.

Johnson, B.A., Brent, D.A., Bridge, J., Connolly, J., 1998. The

familial aggregation of adolescent suicide attempts. Acta

Psychiatr. Scand. 97, 18–24.

Kelly, T.M., Mann, J.J., 1996. Validity of DSM-III-R diagnosis by

psychological autopsy: a comparison with clinician ante-mortem

diagnosis. Acta Psychiatr. Scand. 94, 337–343.

Kelly, D.L., Shim, J.C., Feldman, S.M., Yu, Y., Conley, R.R.,

2004. Lifetime psychiatric symptoms in persons with schizo-

phrenia who died by suicide compared to other means of

death. J. Psychiatr. Res. 38, 531–536.

Kim, C., Lesage, A., Seguin, M., Chawky, N., Vanier, C., Lipp, O.,

Turecki, G., 2003. Patterns of co-morbidity in male suicide

completers. Psychol. Med. 33, 1299–1309.

Kim, C.D., Seguin, M., Therrien, N., Riopel, G., Chawky, N.,

Lesage, A.D., Turecki, G., 2005. Familial aggregation of

suicidal behavior: a family study of male suicide com-

pleters from the general population. Am. J. Psychiatry 162,

1017–1019.

King, E.A., Baldwin, D.S., Sinclair, J.M., Baker, N.G., Campbell,

M.J., Thompson, C., 2001. The Wessex Recent In-Patient

Suicide Study, 1. Case–control study of 234 recently discharged

psychiatric patient suicides. Br. J. Psychiatry 178, 531–536.

Kreyenbuhl, J.A., Kelly, D.L., Conley, R.R., 2002. Circumstances

of suicide among individuals with schizophrenia. Schizophr.

Res. 58, 253–261.

Kuo, C.J., Tsai, S.Y., Lo, C.H., Wang, Y.P., Chen, C.C., 2005. Risk

factors for completed suicide in schizophrenia. J. Clin.

Psychiatry 66, 579–585.

Lesage, A.D., Boyer, R., Grunberg, F., Vanier, C., Morissette, R.,

Menard-Buteau, C., Loyer, M., 1994. Suicide and mental

disorders: a case–control study of young men. Am. J. Psychiatry

151, 1063–1068.

Malone, K.M., Haas, G.L., Sweeney, J.A., Mann, J.J., 1995. Major

depression and the risk of attempted suicide. J. Affect. Disord.

34, 173–185.

Mann, J.J., Waternaux, C., Haas, G.L., Malone, K.M., 1999.

Toward a clinical model of suicidal behavior in psychiatric

patients. Am. J. Psychiatry 156, 181–189.

Mann, J.J., Huang, Y.Y., Underwood, M.D., Kassir, S.A., Oppen-

heim, S., Kelly, T.M., Dwork, A.J., Arango, V., 2000. A

serotonin transporter gene promoter polymorphism (5-

HTTLPR) and prefrontal cortical binding in major depression

and suicide. Arch. Gen. Psychiatry 57, 729–738.

Marttunen, M.J., Aro, H.M., Henriksson, M.M., Lonnqvist, J.K.,

1991. Mental disorders in adolescent suicide. DSM-III-R axes

I and II diagnoses in suicides among 13- to 19-year-olds in

Finland. Arch. Gen. Psychiatry 48, 834–839.

Muller, D.J., Barkow, K., Kovalenko, S., Ohlraun, S., Fangerau, H.,

Kolsch, H., Lemke, M.R., Held, T., Nothen, M.M., Maier, W.,

Heun, R., Rietschel, M., 2005. Suicide attempts in schizophre-

nia and affective disorders with relation to some specific

demographical and clinical characteristics. Eur. Psychiatr. 20,

65–69.

A. McGirr et al. / Schizophrenia Research 84 (2006) 132–143 143

Palmer, B.A., Pankratz, V.S., Bostwick, J.M., 2005. The lifetime

risk of suicide in schizophrenia: a reexamination. Arch. Gen.

Psychiatry 62, 247–253.

Plutchik, R., van Praag, H.M., Conte, H.R., 1989. Correlates of

suicide and violence risk: III. A two-stage model of counter-

vailing forces. Psychiatry Res. 28, 215–225.

Potkin, S.G., Alphs, L., Hsu, C., Krishnan, K.R., Anand, R., Young,

F.K., Meltzer, H., Green, A., 2003. Predicting suicidal risk in

schizophrenic and schizoaffective patients in a prospective two-

year trial. Biol. Psychiatry 54, 444–452.

Roy, A., 1982. Suicide in chronic schizophrenia. Br. J. Psychiatry

141, 171–177.

Roy, A., Segal, N.L., Centerwall, B.S., Robinette, C.D., 1991.

Suicide in twins. Arch. Gen. Psychiatry 48, 29–32.

Roy, A., Segal, N.L., Sarchiapone, M., 1995. Attempted suicide

among living co-twins of twin suicide victims. Am. J.

Psychiatry 152, 1075–1076.

Rudd, M.D., Dahm, P.F., Rajab, M.H., 1993. Diagnostic comorbid-

ity in persons with suicidal ideation and behavior. Am. J.

Psychiatry 150, 928–934.

Schwartz, R.C., Smith, S.D., 2004. Suicidality and psychosis: the

predictive potential of symptomatology and insight into illness.

J. Psychiatr. Res. 38, 185–191.

Shafii, M., Steltz-Lenarsky, J., Derrick, A.M., Beckner, C.,

Whittinghill, J.R., 1988. Comorbidity of mental disorders in

the post-mortem diagnosis of completed suicide in children and

adolescents. J. Affect. Disord. 15, 227–233.

Shearer, S.L., Peters, C.P., Quaytman, M.S., Wadman, B.E., 1988.

Intent and lethality of suicide attempts among female borderline

inpatients. Am. J. Psychiatry 145, 1424–1427.

Sinclair, J.M., Mullee, M.A., King, E.A., Baldwin, D.S., 2004.

Suicide in schizophrenia: a retrospective case–control study of

51 suicides. Schizophr. Bull. 30, 803–811.

Soloff, P.H., Lis, J.A., Kelly, T., Cornelius, J., Ulrich, R., 1994. Risk

factors for suicidal behavior in borderline personality disorder.

Am. J. Psychiatry 151, 1316–1323.

Statham, D.J., Heath, A.C., Madden, P.A., Bucholz, K.K., Bierut,

L., Dinwiddie, S.H., Slutske, W.S., Dunne, M.P., Martin, N.G.,

1998. Suicidal behaviour: an epidemiological and genetic study.

Psychol. Med. 28, 839–855.

Vieta, E., Nieto, E., Gasto, C., Cirera, E., 1992. Serious suicide

attempts in affective patients. J. Affect. Disord. 24, 147–152.

Westermeyer, J.F., Harrow, M., Marengo, J.T., 1991. Risk for

suicide in schizophrenia and other psychotic and nonpsychotic

disorders. J. of Nerv. Ment. Dis. 179, 259–266.

Zhang, J., Conwell, Y., Wieczorek, W.F., Jiang, C., Jia, S., Zhou,

L., 2003. Studying Chinese suicide with proxy-based data:

reliability and validity of the methodology and instruments in

China. J. of Nerv. Ment. Dis. 191, 450–457.