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Comprehensive Psychiatry xx (2013) xxx–xxxwww.elsevier.com/locate/comppsych

The characteristics of unacceptable/taboo thoughts inobsessive–compulsive disorder

Vlasios Brakouliasa,⁎, Vladan Starcevica, David Berleb, Denise Milicevicb, Karen Mosesb,Anthony Hannanb, Peter Sammutc, Andrew Martind

aUniversity of Sydney, Sydney Medical School-Nepean, Discipline of Psychiatry, Sydney/Penrith, NSW, AustraliabNepean Anxiety Disorders Clinic, Nepean/Blue Mountains Local Health District, Penrith, NSW, Australia

cNepean Hospital, Department of Psychiatry, Penrith, NSW, AustraliadNHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia

Abstract

Background: In the quest to unravel the heterogeneity of obsessive–compulsive disorder (OCD), an increasing number of factor analyticstudies are recognising unacceptable/taboo thoughts as one of the symptom dimensions of OCD.Aims: This study aims to examine the characteristics associated with unacceptable/taboo thoughts.Methods: Using the Yale–Brown Obsessive–Compulsive Scale Symptom Checklist (YBOCS-SC) with 154 individuals with OCD,obsessive–compulsive symptoms were subjected to principal components analysis. The characteristics associated with the resulting symptomdimensions were then assessed using logistic and linear regression techniques.Results: Unacceptable/taboo thoughts comprised of sexual, religious and impulsive aggressive obsessions, and mental rituals. Higher scoreson an unacceptable/taboo thoughts symptom dimension were predicted by higher Y-BOCS obsession subscores, Y-BOCS time preoccupiedby obsessions scores, Y-BOCS distress due to obsessions scores, importance of control of thought ratings, male gender, and having hadtreatment prior to entering into the study. Unacceptable/taboo thoughts were also predicted by greater levels of hostility, and a past history ofnon-alcohol substance dependence.Conclusions: An unacceptable/taboo thought symptom dimension of OCD is supported by a unique set of associated characteristics thatshould be considered in the assessment and treatment of individuals with these symptoms.Crown Copyright © 2013 Published by Elsevier Inc. All rights reserved.

1. Introduction

Unacceptable/taboo thoughts, also known as “pureobsessions”, refer to impulsive aggressive, sexual andreligious obsessions. The observation that some obsessionsoccurred in the apparent absence of compulsions was firstmade by Baer [1] in a study employing factor analysistechniques. Since then, there have been a number of factor

No conflicts of interest. This study was funded by the Nepean MedicalResearch foundation, a competitive Pfizer Neuroscience Grant and a grantfrom the Discipline of Psychiatry at The University of Sydney.

⁎ Corresponding author. Nepean Hospital, Department of Psychiatry,PO Box 63, Penrith, NSW 2751, Australia. Tel.: +61 2 4734 2585; fax: +612 4734 3343.

E-mail addresses: vbrakoulias@bigpond.com,vlasios.brakoulias@sydney.edu.au (V. Brakoulias).

0010-440X/$ – see front matter. Crown Copyright © 2013 Published by Elseviehttp://dx.doi.org/10.1016/j.comppsych.2013.02.005

analytic studies [2–9] that have revealed a symptomdimension of obsessive–compulsive disorder (OCD) char-acterised predominantly by obsessions and in particularaggressive, sexual and religious obsessions. More recently,studies [10,11] have demonstrated that “pure obsessions” is amisnomer in that unacceptable/taboo thoughts tend to beaccompanied by compulsions.

Unacceptable/taboo thoughts are distinctly ego-dystonicwith a repugnant quality that tends not to be so prominentin other OCD symptoms [12]. As their name suggests, thecontent of these obsessions typically involves unacceptable,taboo or forbidden themes such as stabbing a relative,incest or blasphemy. Studies have associated unacceptable/taboo thoughts with mental rituals [10], reassurance-seeking [6,10], avoidance [13,14], good insight [15], malegender [16,17], and being more likely to seek professionalhelp [18].

r Inc. All rights reserved.

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In addition to the obvious phenomenological differencesbetween unacceptable/taboo thoughts and other OCDsymptoms, unacceptable/taboo thoughts also appear tohave clinical utility as they have been associated with adifferential response to treatment. Although studies examin-ing the response of unacceptable/taboo thoughts to pharma-cotherapy have resulted in conflicting findings [19], somestudies investigating the response to behavioural interven-tions [20–22] have reported a poorer outcome.

This study aimed to illustrate that unacceptable/taboothoughts are associated with different characteristics to othersymptom dimensions of OCD and that these characteristicsmay have implications for the treatment of individuals withunacceptable/taboo thoughts. It was hypothesised thatunacceptable/taboo thoughts would be associated withgreater severity, specifically higher Y-BOCS obsessionscores and higher levels of distress. These hypotheses werebased on clinical observation and the findings of previousstudies [23,24]. Having hypothesized that greater degrees ofseverity and distress would be associated with unacceptable/taboo thoughts, it was additionally hypothesised thatunacceptable/taboo thoughts would be associated withhigher rates of having obtained treatment prior to enteringthe study, greater reassurance-seeking, greater levels ofavoidance, higher rates of comorbid depression and strongerbeliefs relating to a need to control one's thoughts. Thesehypotheses were based on limited evidence relatingunacceptable/taboo thoughts to higher rates of previoustreatment [18], greater reassurance-seeking [6,10], greaterlevels of avoidance [13,14], higher rates of comorbiddepression [25,26] and cognitive beliefs relating to theimportance of controlling one's thoughts [27–30].

2. Methods

2.1. Recruitment

This report has resulted from the Nepean OCD Study,conducted in Sydney and several other Australian cities.Participants (N = 154) were recruited from the NepeanAnxiety Disorders Clinic, OCD support groups, newspaperadvertisements and referrals from general practitioners,psychiatrists, clinical psychologists and mental healthservices. Participants were included if they had a primarydiagnosis of OCD which was determined on the basis of aclinician-administered semi-structured interview, the MiniInternational Neuropsychiatric Interview plus version (MINI[31,32]), and the qualifier that OCD was the condition forwhich they sought help or which caused the most distress orimpairment in functioning. Individuals with a currentcomorbid diagnosis of psychosis, bipolar affective disorder,a pervasive developmental disorder, severe intellectualdisability, or substance abuse or dependence were excluded.The MINI was also used to determine co-occurringdiagnoses and age of onset. Participants needed to be overthe age of 18. Institutional ethics committee approval was

obtained prior to commencing the study and all participantsprovided signed informed consent.

2.2. Measures

Participant characteristics were assessed via structuredclinical interviews and self-report instruments. In this article,we report findings derived from standard demographics, theMINI, the Yale–Brown Obsessive–Compulsive Scale (Y-BOCS) [33], Avoidance and Reassurance-seeking Interview,Overvalued Ideas Scale (OVIS) [34], Symptom Checklist90-Revised (SCL-90R) [35] and Obsessive Beliefs Ques-tionnaire (OBQ) [36,37].

The MINI (plus version) is a clinician-administered semi-structured interview that was used to determine co-occurringDSM-IV diagnoses and their age of onset, in addition toascertaining whether the DSM-IV criteria for OCD havebeen met. The MINI has been validated against other widelyused structured diagnostic interviews and its psychometricproperties have been good [38,39].

The severity of OCD was assessed by means of the Y-BOCS, whereas OCD symptoms were assessed via the Y-BOCS Symptom Checklist (YBOCS-SC). The YBOCS-SCis a semi-structured interview which includes a comprehen-sive list of 64 obsessions and compulsions arranged bycontent into 15 categories. The categories for obsessions are:aggressive; contamination; sexual; hoarding/saving; reli-gious; symmetry/exactness; miscellaneous; and somatic. Thecategories for compulsions are: cleaning/washing; checking;repeating; counting; ordering/arranging; hoarding/collecting;and miscellaneous. All the categories were used for theprincipal components analysis (PCA) except for aggressiveand miscellaneous. Two items from the aggressive obses-sions category were re-classified as “unintentional harm”.These were: “fear will harm others because not carefulenough” and “fear will be responsible for something elseterrible happening”. All other items were categorised as“impulsive aggression” obsessions. This method has beenused in other studies [3,4] in an attempt to reduce theheterogeneity within the aggressive obsessions category.Similarly, in an attempt to reduce the heterogeneity of themiscellaneous categories [10], only the item “mental rituals”was used.

Interviews were conducted by a psychiatrist or clinicalpsychologist trained in the use of the MINI and YBOCS-SC.Interrater reliability was assessed for the first 49 participants(this involved two raters completing the MINI and theYBOCS-SC in the same assessment without corroboratingtheir findings), and for the YBOCS-SC categories this wasexcellent (94.3% agreement).

Avoidance and reassurance-seeking were assessed by aninterview-based instrument that was constructed for thestudy and administered alongside the Y-BOCS. Thisinstrument assesses the presence of avoidance and/orreassurance-seeking and the extent of avoidance and/orreassurance-seeking with a 5-point Likert scale. Avoidance

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is assessed with the question: “Have you been avoidinganything because of your obsessions/thoughts or becauseyou were concerned you would perform compulsions?”Reassurance-seeking is assessed with the question: “Haveyou been asking anyone to reassure you because of yourobsessions/thoughts or because you think you did some-thing wrong or punishable?” Both questions give examplesto ensure the subject has understood what is meant byavoidance and reassurance-seeking in the context of OCD.The instrument has demonstrated good convergent validitywith higher scores on avoidance and reassurance-seekingpredicting greater OCD severity and higher levels ofanxiety [40,41].

Insight and other characteristics of belief related to OCDwere measured using the OVIS. This structured clinicalinterview has been shown to have better predictive validitythan the single item that assesses insight on the Y-BOCS [42].

Symptom distress and psychopathology were measuredby the SCL-90R. This 90-item psychometrically soundinstrument [43], provides scores on the Global SeverityIndex and nine subscales: Somatization, Obsessive–compul-sive, Interpersonal sensitivity, Depression, Anxiety, Hostil-ity, Phobic anxiety, Paranoid ideation and Psychoticism.

Cognitive styles along the dimensions of responsibility/threat estimation, perfectionism/intolerance of uncertaintyand importance/control of thoughts were assessed with the44-item OBQ. The psychometric properties of the OBQ insamples with OCD, where it has been used in a large numberof studies, have been reported to be good [44].

2.3. Statistical methods

All data were entered into the Statistical Package for theSocial Sciences (SPSS) version 17 [45] and analysed.Additional analyses were conducted using SAS version 9.2[46]. PCA was conducted on the 15 YBOCS-SC categoriesas described above. Oblique (direct Oblimin) and orthogonal(Varimax) rotational methods yielded comparable results.The study used the technique for factor loading described byBaer (1994) and Mataix-Cols et al. (1999) when analysingthe YBOCS-SC. According to this technique, Y-BOCSsymptom categories regarded as principal symptoms weregiven a value of 2, whereas other symptoms categories thatwere currently present were given a value of 1 and whenthere was no symptom in a given category, it was given avalue of 0.

Suitability of the data for PCA was assessed using aKaiser–Meyer–Olkin Measure of Sampling Adequacyvalue of 0.6 or above [47,48] and a Bartlett's Test ofSphericity significance value less than 0.05 [49]. Parallelanalysis [50,51] was used to determine the number offactors to be extracted for rotation. Items loading N0.4 wereregarded as robust.

A series of regression models were constructed toexamine the relationship between each participant charac-teristic assessed (fitted individually as the outcome variable)

and the 5 YBOCS-SC-derived symptom dimensions (fittedtogether as covariates). Multiple linear regression wasapplied to the continuous outcome variables and logisticregression to the binary outcome variables. In each case abackwards elimination approach was applied to the fullregression model, comprising the 5 YBOCS-SC-derivedsymptom dimensions, in order to produce a parsimoniousmodel comprising those YBOCS-SC-derived symptomdimensions that remained statistically significant (at the5% level). Results from final models that included theunacceptable/taboo thoughts symptom dimension as acovariate are presented in the results. The False DiscoveryRate (FDR) approach was used to adjust P-values for themultiple comparisons [52,53].

3. Results

The characteristics of the sample are shown in Table 1.The specified YBOCS-SC categories that were subjectedto PCA yielded a five-factor structure explaining 64.9% ofthe variance (Table 2). This included an unacceptable/taboo thoughts symptom factor that explained 8.7% of thevariance and that consisted of impulsive aggressive, sexualand religious obsessions and mental rituals. Logistic andlinear regression analyses revealed that higher Y-BOCSobsession scores, higher levels of distress, more timespent on obsessions, greater levels of hostility, beliefsregarding the importance of controlling one's thoughts,having had treatment prior to the study, being male andhaving had a past diagnosis of non-alcohol drugdependence significantly predicted higher scores on theunacceptable/taboo factor after adjustment for multiplecomparisons (Table 3). There was no significant relation-ship between unacceptable/taboo thoughts and avoidance,reassurance-seeking and level of insight.

4. Discussion

This study presented new findings indicating thatunacceptable/taboo thoughts might be characterised byhigher rates of previous non-alcohol substance dependenceand greater levels of hostility. One may hypothesise that thereis a need to use substances to reduce the distress associatedwith unacceptable/taboo thoughts, or that substance abuseplays an aetiological role in the occurrence of theseobsessions. However, the cross-sectional nature of ourstudy does not allow us to speculate about the direction ofcausality, if any, between unacceptable/taboo thoughts andsubstance abuse. The role of substance abuse in the aetiologyof unacceptable/taboo thoughts is not supported by thefinding that 70% of individuals with OCD and comorbidsubstance abuse believe that their OCD preceded theirsubstance abuse [54]. Although there are higher rates ofsubstance dependence in individuals with OCD [55–57], no

Table 1Characteristics of the study participants.

Characteristic OCD Sample(N = 154)

Age (in years)Mean (standard deviation) 45.5 (16.2)Median 47.0Range 18 to 79

Y-BOCS total scoreMean (standard deviation) 22.0 (6.7)

n %GenderMale 62 40.3Female 92 59.7

Marital statusNever married 56 36.4Married/in a de facto relationship 60 39.0Divorced/separated 32 20.8Widowed 6 3.8

Number of childrenNil 73 47.3One or more 81 52.7

Employment statusFull-time (≥24 h/week) 42 27.3Part-time (b24 h/week) 21 13.7Unemployed 91 59.0

Highest level of educational attainmentPrimary school 4 2.6Secondary school 78 50.6Technical college certificate or diploma 40 26.0University degree 32 20.8

Comorbid conditionsGeneralised anxiety disorder 49 31.8Specific phobia 32 20.8Past alcohol abuse 28 18.2Major depressive disorder 25 16.2Social phobia 25 16.2Panic disorder 21 13.6Tic disorder 17 11.0Past alcohol dependence 16 10.4Past psychotic disorder 14 9.1Past non-alcohol drug abuse 11 7.1Past non-alcohol drug dependence 6 3.9Hypochondriasis 3 1.9

Treatment with psychotropic agent at thetime of assessment

93 60.4

Previous behavioural intervention 71 46.1

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study reported higher rates in individuals with unacceptable/taboo thoughts compared to individuals with other OCDsymptoms. Furthermore, the relationship between currentsubstance abuse or dependence was not assessed in this studyas such patients were excluded from participating. Therefore,the finding of an association between unacceptable/taboothoughts and past substance abuse requires replication.Neuroimaging data [58] have revealed similarities betweenpathways involved with reward dependence in addiction andpathways involved in OCD. These suggest that addiction, andin particular substance dependence [57,59,60] acts to rewardin a similar manner to compulsions. In the absence of overtcompulsions with unacceptable/taboo thoughts, there may bean increased tendency to develop substance dependence.

According to the SCL-90R, hostility refers to thoughts,feelings, or actions that are characteristic of the negativeaffect state of anger and this includes aggression, irritability,rage and resentment [35]. Although it is possible thatrepetitive, distressing unacceptable/taboo thoughts maymake the person more hostile, hostility may also predisposeto the development of unacceptable/taboo thoughts andperhaps to substance abuse too. Our finding that individualswith unacceptable/taboo thoughts are more likely to be malemay also influence the rates of substance abuse and hostilitylevels, as these are both more associated with males [61–63].As studies have associated low levels of serotonin withhostility [64], some authors have concluded that aggressiveobsessions may be more effectively treated with SSRIs [65].

The finding of a link between unacceptable/taboothoughts and male gender is consistent with previous studies[16,17,66]. Potential explanations for this associationinclude sexual dimorphism in brain regions accounting forunacceptable/taboo thoughts, as has been suggested forcontamination/cleaning symptoms [17,67], or the existenceof gender-specific environmental factors that mediate theexpression of unacceptable/taboo thoughts.

There were also a number of other findings that wereconsistent with previous studies and thus support thevalidity of the new findings. As hypothesised, theunacceptable/taboo thoughts symptom dimension revealedby factor analysis in this study comprised mental rituals,sexual obsessions, religious obsessions and impulsiveaggression obsessions. The inclusion of mental rituals inan unacceptable/taboo thoughts symptom dimension ofOCD replicates the findings of a previous study [10]. Insupport of the ego-dystonic nature of unacceptable/taboothoughts, the Y-BOCS revealed that higher obsessionscores, higher obsession-related distress, and more timespent on obsessions predicted higher scores on theunacceptable/taboo symptom factor. The OBQ confirmedprevious findings relating the importance of control ofthoughts to unacceptable/taboo thoughts [27,29,30,68].Individuals with unacceptable/taboo thoughts were alsomore likely than individuals with other OCD symptoms tohave received treatment for their condition, and this isagain consistent with previous findings [18]. These findingssuggest that unacceptable/taboo thoughts are experiencedwith much distress, which may motivate many sufferers toseek help and treatment earlier than individuals with othersymptoms of OCD.

Unlike previous studies [6,10,13], there was no relation-ship between unacceptable/taboo thoughts and avoidance orreassurance-seeking. This finding is likely to be explained bydifferences in the methods used to assess OCD symptoms,avoidance and reassurance-seeking. This primarily relates tothe grouping of checking compulsions with unacceptable/taboo thoughts in previous studies. Reassurance-seeking isviewed by some [69] as a form of checking and there aresome studies indicating that reassurance-seeking has astronger relationship with checking than unacceptable/

Table 2The frequency of principal YBOCS-SC categories or items and Varimax-rotated factor structure using three-point ordinal rating principal components analysis(N = 154).

YBOCS-SC categories⁎ Frequency (%) Hoarding Contamination/Cleaning

Doubt/Checking

Symmetry/Ordering

Unacceptable/TabooThoughts

Hoarding/saving obsessions 20.8 0.964 −0.126 −0.075 −0.058 −0.083Hoarding compulsions 23.4 0.957 −0.145 −0.076 −0.042 −0.069Contamination obsessions 26.6 −0.165 0.921 −0.060 0.018 −0.025Cleaning/washing compulsions 26.0 −0.108 0.913 −0.075 0.036 −0.008Symmetry obsessions 9.1 −0.046 −0.003 0.026 0.953 0.061Ordering/arranging compulsions 7.1 −0.047 0.033 0.037 0.952 −0.048Mental rituals⁎ 5.2 0.039 0.071 −0.105 0.042 0.745Sexual obsessions 3.2 −0.081 0.009 0.120 −0.104 0.701Impulsive aggression⁎ 17.5 −0.187 −0.223 0.410 0.014 0.535Religious obsessions 1.9 −0.037 0.054 0.118 0.209 0.550Checking compulsions 29.9 −0.095 0.109 0.848 −0.012 −0.014Unintentional harm⁎ 16.9 −0.139 −0.109 0.709 0.017 0.108Repeating rituals 3.9 0.151 0.157 0.565 0.134 0.101Somatic obsessions 3.2 0.017 0.372 0.398 −0.083 0.126Counting compulsions 13.0 −0.092 0.046 0.129 0.202 0.026Percentage of variance explained (%) - 18.5 14.8 13.3 9.6 8.7

Robust loadings (N0.4) are printed in bold and are underlined.⁎ Symptoms with an asterisk indicate that “mental obsessions” are an item from the miscellaneous compulsions category and that “unintentional harm” and

“impulsive aggression” pertain to certain items from the aggressive obsessions category.

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taboo thoughts [69–71]. In addition, a more comprehensiveassessment of reassurance-seeking was conducted in thisstudy compared to previous studies [6,10] where the singlemiscellaneous item of the Y-BOCS (“Need to ask, tell orconfess”) was used to represent reassurance-seeking.

The finding that participants with unacceptable/taboothoughts were more likely to have received treatment wouldsupport an association with good insight. However, arelationship between unacceptable/taboo thoughts andinsight was absent in this study. Unlike the previous positivestudy [15] which used a single item of the Y-BOCS to assessinsight and combined “forbidden” thoughts with checking,insight in our study was measured with a tool specificallydesigned to assess belief in OCD (the OVIS). Despite using avalidated assessment tool that assesses insight in a multi-dimensional manner, there are many limitations that arisewhen assessing insight. These limitations relate to thecomplex nature of insight, the difficulties associated withidentifying a belief relating to a subject's primary OCDsymptoms and the inconsistent use of terms used tocharacterise belief in assessment tools [72].

Although the finding of this study in relation to thefrequency of co-occurring depression did not reach statisticalsignificance after adjustment for multiple comparisons, thisfinding is likely to require further investigation. Previousstudies [25,26] indicating an association between unaccept-able/taboo thoughts and higher comorbidity with majordepression again grouped unacceptable/taboo thoughts withchecking. The higher levels of distress associated withunacceptable/taboo thoughts may be a confounding factor inthe assessment of depression. The increased rate of seekingtreatment among participants with unacceptable/taboothoughts may reflect increased levels of motivation and

energy, or perceived worthiness or hope. These character-istics are less likely to be present in participants withcomorbid depression.

The number of instruments used in the study was limitedby the potential burden on volunteering participants. Thiswas a cross-sectional study focusing primarily on descrip-tive characteristics, which precluded us from examiningpossible aetiological factors and longitudinal relationshipsthat may be relevant for unacceptable/taboo thoughts.Despite the widespread use of the Y-BOCS in assessingsymptoms for factor analysis, its use has been criticised aspotentially biased, because symptoms are categorised priorto the analysis. As discussed, this has resulted in categoriessuch as aggressive obsessions and miscellaneous compul-sions, which are generally regarded as heterogeneous. Thesample size is relatively small if we consider thatparticipants with unacceptable/taboo thoughts representeda proportion of the total sample of subjects with OCD. Thefinding relating to past non-alcohol substance dependence isalso limited by the small number of participants whoreported past substance dependence.

5. Conclusions

Unacceptable/taboo thoughts appear to form a distinctsymptom dimension of OCD and their validity is furthersupported by their association with descriptive characteris-tics that are not commonly associated with other OCDsymptom dimensions. The ego-dystonic nature of unac-ceptable/taboo thoughts and their association with the beliefthat it is important to control one's thoughts supportpsychological therapies that target underlying beliefs and

Table 3Regression analyses results.

Dependent variable Unacceptable/taboo thoughts symptom dimension

Logistic regression results (Dichotomous variables): Percentage of whole sample N (%) Odds Ratioa 95% Confidence Interval Standard Error P-value

MINI diagnosis• Major depressive episode: Current 25 (19.4%) 3.94 1.7–12.3 1.78 0.0180• Alcohol abuse: Past 28 (18.2%) 3.82 1.3–11.5 1.75 0.0167• Non-alcohol drug dependence: Past* 6 (3.9%) 27.90 3.3–233.0 2.95 0.0021*• Hypochondriasis: Past 4 (2.6%) 11.31 1.2–104.4 3.11 0.0325

Treatment prior to entry to study* 40 (30.0%) 9.09 2.2–33.3 2.09 0.0025*Male gender* 62 (40.3%) 5.69 2.1–15.7 1.68 0.0008*Being a parent 79 (51.3%) 0.26 0.1–0.7 1.66 0.0075

Dependent variable Unacceptable/taboo thoughts symptom dimension

Linear regression results (Continuous variables): Parameter Estimate (β)b 95% Confidence Interval Standard Error P-value

Y-BOCS obsession score* 2.41 0.7–4.1 0.86 0.0058*Y-BOCS total score 4.13 1.1–7.2 1.54 0.0082Y-BOCS: Time spent on obsessions* 0.85 0.4–1.3 0.24 0.0006*Y-BOCS: Interference due to obsessions 0.71 0.2–1.2 0.24 0.0040Y-BOCS: Distress due to obsessions* 0.96 0.6–1.4 0.21 b0.0001*OBQ: Importance/control of thought* 32.77 28.7–36.8 2.06 b0.0001*SCL-90R: Hostility* 0.60 0.2–1.0 0.60 0.0021*Age at assessment −9.30 −16.3–−2.3 3.52 0.0092

Only models that obtained p-values lower than 0.05 for the unacceptable/taboo thoughts symptom dimension are shown. P-values less than 0.007 are asteriskedand represent findings that remained statistically significant after application of the False Discovery Rate (FDR) procedure.

a Reflects the increase in the odds of an outcome for each 1-point increase in the unacceptable/taboo thoughts symptom dimension.b Reflects the increase in outcome score for each 1-point increase in the unacceptable/taboo thoughts symptom dimension.

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cognitive processes in addition to the standard behaviouraltreatment approach to OCD in the form of ERP. Substanceabuse and hostility may also be associated with unaccept-able/taboo thoughts. Although this finding requires repli-cation, it indicates that clinicians should not neglectsubstance abuse in their assessment of individuals withunacceptable/taboo thoughts and that they should also noteassociated hostility, if present. An awareness of thepresence of these associated characteristics may assist inthe understanding of the development and/or maintenanceof unacceptable/taboo thoughts.

Acknowledgment

The authors are grateful to Colin Slocombe from ACEDAAdelaide, Michelle Graeber from ARCVIC Melbourne,Scott Blair-West of the Melbourne Clinic, the Blacktownand Kogarah OCD Support Groups, the Mental HealthAssociation of NSW and the Penrith Mental HealthPractitioners' Network.

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