Repetitive behaviors in Tourette's syndrome and OCD with and without tics: what are the differences?

Gilles de la Tourette Syndrome (GTS) and obsessive-compulsive disorder (OCD) share obsessive-compulsive phenomena. The aims of this study were to compare the OC symptom distribution between GTS and OCD and to investigate whether a subdivision of these phenomena into obsessions, compulsions and 'impulsions' is useful in distinguishing GTS and OCD patients. Thirty-two GTS, 31 OCD (10 with tics, 21 without tics) and 29 control subjects were studied using the Leiden repetitive behaviors semi-structured interview to assess GTS as well as OCD-related behaviors. Each reported repetitive thought or action was evaluated on the presence of anxiety and on goal-directedness. This information was used to define whether the behavior was an obsession, compulsion, or 'impulsion'. Both the GTS and OCD study groups showed higher scores than control subjects on rating scales measuring depression, OC behavior and anxiety. In GTS, Y-BOCS severity scores and trait anxiety were lower than in the OCD groups. Furthermore, GTS patients differed from OCD patients in the distribution of symptoms. Aggressive repetitive thoughts, contamination worries and washing behaviors were reported more frequently by tic-free OCD, while mental play, echophenomena, touching and (self)-injurious behaviors were reported more frequently by GTS. OCD individuals with tics were intermediate, but closer to tic-free OCD. GTS individuals reported significantly more 'impulsions' and fewer obsessions and compulsions than OCD individuals with and without tics. Factor analysis revealed three factors accounting for 44% of the variance, resulting in an 'impulsive' factor related to GTS, a 'compulsive' factor related to OCD and an 'obsessive' factor related to tic-free OCD. In conclusion, OCD individuals reported more anxiety and goal-directedness associated with their behaviors than did GTS subjects. The distinction between obsessions, compulsions and impulsions is of importance in identifying Tourette-related vs. non-Tourette-related repetitions.     

Symptom dimensions in obsessive-compulsive disorder: factor analysis on a clinician-rated scale and a self-report measure

Although obsessive-compulsive disorder (OCD) is regarded as a unitary nosological entity, it encompasses a rich variety of heterogeneous mental and behavioural phenomena. The identification of clinical subtypes within this broad concept has been a focus of attention in recent years. In the present study, we administered a clinician-rated scale, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) with the Y-BOCS Symptom Checklist (Y-BOCS CL), as well as a self-report questionnaire, the Padua Inventory revised (PI-R), to 150 outpatients with OCD. A principal component analysis on the Y-BOCS CL, along with the PI-R, identified 6 consistent symptom clusters: (1) contamination obsessions and cleaning compulsions, (2) sexual/religious/somatic obsessions and checking, (3) high risk assessment and checking, (4) impulses and fear of loss of control, (5) need for symmetry and exactness, and ordering and counting compulsions, and finally (6) rumination. The Y-BOCS CL and PI-R showed great overlap and consistency regarding content and severity of the OCD symptoms. On inspection of items with identical content, only half of the items showed significant agreement. Both inventories have unique factors: rumination is represented solely in the PI-R, somatic obsessions and checking solely in the Y-BOCS CL. This means that the use of both clinician-administered and self-report measures is recommended, so that the entire spectrum of symptoms is represented.     

Use of factor analysis to detect potential phenotypes in obsessive-compulsive disorder

This study aimed to identify symptom dimensions in obsessive-compulsive disorder (OCD) in order to reveal distinct clinical phenotypes. Factor analysis of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) checklist on item level was performed on data from 335 outpatients with primary OCD. The relationship of demographic and clinical characteristics to the resulting factor scores was examined. A principal component analysis identified the following five consistent symptom dimensions: (1) contamination and cleaning, (2) aggressive, sexual and religious obsessions, (3) somatic obsessions and checking, (4) symmetry and counting/arranging compulsions and (5) high-risk assessment and checking. We observed significant differences in sex distribution, age of onset, Y-BOCS scores and familial prevalence of OCD in relation to the symptom dimensions. These findings provide further evidence for distinct clinical phenotypes in OCD.     

OCD symptoms in a sample of Turkish patients: a phenomenological picture

This study aimed to investigate the clinical features of obsessive-compulsive disorder (OCD) and the possible association between obsessive-compulsive symptoms and culture-related characteristics in a sample of Turkish patients with OCD. We studied 141 patients with OCD (according to DSM-IV criteria) consecutively admitted to our outpatient clinic during the period from February 1998 to December 2003. We used the Turkish version of the Structured Clinical Interview for DSM-IV (SCID) to interview all patients, and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) to assess obsessive-compulsive symptoms and severity. The onset of OCD symptoms was earlier in males. Major depression was the most common comorbid disorder (30.5%). The most commonly occurring obsessions were contamination (56.7%), aggression (48.9%), and somatic (24.1%), followed by religious (19.9%), symmetry (18.4%), and sexual imagery (15.6%). Symmetry and sexual obsessions, and checking compulsions and rituals, tended to be more common in male patients. Dirt and contamination obsessions and washing compulsions were slightly more common in females. The vast majority of patients with religious obsessions (83%) and half of the patients with sexual obsessions had compulsions that included religious practices. Also, patients with sexual and religious obsessions had delayed seeking professional help.     

Personality dimensions in obsessive-compulsive disorder: relation to clinical variables

Research on the relationship between personality factors and obsessive-compulsive disorder (OCD) has proved difficult to interpret due to conceptual problems including a lack of consensus on the model of personality employed as a framework as well as a failure to consider the clinical heterogeneity of the disorder. The aim of this study was to examine the dimensional personality profile associated with OCD and to determine whether any relationship exists between personality factors and clinical variables in a sample of 60 OCD outpatients who were administered Cloninger's Temperament and Character Inventory (TCI). The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Hamilton Depression Rating Scale (HDRS) and the Y-BOCS symptom checklist were used to assess the severity of obsessive-compulsive and depressive symptoms and the presence of the main OCD symptom dimensions. OCD patients showed significantly higher scores in harm avoidance and lower scores in novelty-seeking, self-directedness and cooperativeness than healthy subjects. These results remained unchanged when only pure OCD patients without comorbid psychiatric conditions were considered. Comorbid depressive symptoms and hoarding obsessions and compulsions were significantly associated with high harm avoidance scores. These results support the existence of a dimensional personality profile associated with OCD and characterized by high harm avoidance and low novelty-seeking, self-directedness and cooperativeness scores, but also emphasize the importance of considering the influence of comorbid clinical conditions or symptom subtypes in addressing the role of personality factors in OCD.     

Korean Self-Report Version of the Yale-Brown Obsessive-Compulsive Scale: Factor Structure,Reliability, and Validity

Objective

Although several self-report versions of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) have been developed and used widely, few psychometric studies have established the construct validity of this measure. Therefore, we developed Korean self-report version of the Y-BOCS and evaluated its factor structure, reliability, and validity.

Methods

A non-clinical student sample (n=206) and a clinical OCD sample (n=199) completed the Korean self-report version and other measures of obsessive-compulsive disorder (OCD), depression, and anxiety.

Results

Consistent with the originally proposed structure, confirmatory factor analyses supported a factor structure comprised of Obsessions and Compulsions factors in the Korean self-report version. Two subscale scores and the total score of the Korean self-report version showed good internal consistency and convergent validity, but relatively poor discriminant validity. Applying a cutoff score of 16, 84% of OCD patients and 93% of the non-clinical sample were classified correctly.

Conclusion

Korean self-report version of the Y-BOCS is a psychometrically sound and valid measure for assessing OCD symptoms as compared with the clinician-administered version. The originally proposed division of OCD severity into obsessions and compulsions appears accurate in the Korean self-report version. The cutoff score for the Korean self-report version needs adjustment based on further researches.     

Religiosity and religious obsessions in obsessive-compulsive disorder.

Religion has often been thought to play a part in the genesis of some cases of obsessive-compulsive disorder (OCD). In this study, we explored the relationship between religiosity, religious obsessions, and other clinical characteristics of OCD. Forty-five outpatients with OCD were evaluated with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the Yale-Brown Obsessive-Compulsive Checklist (Y-BOCC) as well as the Religious Practices Index (RPI), which was developed for this study. On the basis of these evaluations, 42% of the patients were found to have religious obsessions. Despite differences in the frequency of religious obsessions found in this study compared with others, a factor analysis revealed the symptom dimensions to be similar to those found in other OCD samples. There was no significant difference in the overall severity of obsessions and compulsions between patients with and without religious obsessions. RPI scores did not differ significantly between groups. We failed to find a relationship between RPI scores or religious obsessions and any particular type of obsession or compulsion. A logistic regression analysis revealed that the sole predictor of the presence of religious obsessions was a higher number of types of obsessions. In conclusion, we failed to find a conclusive relationship between religiosity and any other clinical feature of OCD, including the presence of religious obsessions. On the other hand, we showed that the patients who tend to have a variety of obsessions are more likely also to have religious obsessions. Thus, religion appears to be one more arena where OCD expresses itself, rather than being a determinant of the disorder.     

Health concerns in patients with obsessive-compulsive disorder

In the present study, individuals with obsessive-compulsive disorder (OCD) who also had excessive health concerns (n = 56) were compared with OCD individuals without such concerns (n = 343) regarding their OCD symptom severity, types of obsessions and compulsions, insight into the irrationality of their obsessions, and prevalence of generalized anxiety disorder. While the presence of health concerns did not affect the severity of OCD symptoms, the groups differed with respect to the types of symptoms displayed: those with health concerns had more somatic and harm obsessions, and checking compulsions: whereas those without such concerns had more contamination obsessions and washing compulsions. The insight of both groups ranged from poor to excellent, yet the number of individuals with poor insight was greater among those with health concerns than those without. Generalized anxiety disorder was also more prevalent among OCD individuals with excessive health concerns.     

Gender-related differences among Turkish patients with obsessive-compulsive disorder

The purpose of the present study was to investigate gender-related sociodemographic and clinical differences among Turkish patients with obsessive-compulsive disorder (OCD). A total of 169 patients diagnosed with OCD by DSM-III-R or DSM-IV criteria were included in this study. Male (n = 73) and female (n = 96) OCD patients were compared with respect to the demographic variables and the scores obtained from the Hamilton Rating Scale for Anxiety (HRSA), the Hamilton Rating Scale for Depression (HRSD) and the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). We found a significantly earlier age at onset in male patients. No significant difference in terms of HARS, HDRS, and Y-BOCS scores was detected between the two groups. We observed a significantly higher frequency of contamination obsessions in females, and that of aggression and sexual obsessions in males. There was no significant difference in terms of the frequency of compulsions between the two groups. We also found that compulsion severity on obsessions/compulsions was higher in females and comorbidity rates of social phobia and schizophrenia were higher in males. Considering our results in combination with those of other studies, similarities rather than differences in gender-related sociodemographic and clinical characteristics of OCD patients across different populations seem to be present.     

Myth of the pure obsessional type in obsessive--compulsive disorder

Background: Several studies have identified discrete symptom dimensions in obsessive–compulsive disorder (OCD), derived from factor analyses of the individual items or symptom categories of the Yale–Brown Obsessive–Compulsive Scale Symptom Checklist (YBOCS‐SC). This study aims to extend previous work on the relationship between obsessions and compulsions by specifically including mental compulsions and reassurance‐seeking. Because these compulsions have traditionally been omitted from prior factor analytic studies, their association to what have been called “pure obsessions” may have been overlooked. Method: Participants ( N =201) were recruited from two multi‐site randomized clinical treatment trials for OCD. The YBOCS‐SC was used to assess OCD symptoms, as it includes a comprehensive list of obsessions and compulsions, arranged by content category. Each category was given a score based on whether symptoms were present and if the symptom was a primary target of clinical concern, and a factor analysis was conducted. Mental compulsions and reassurance‐seeking were considered separate categories for the analysis. Results: Using an orthogonal geomin rotation of 16 YBOCS‐SC categories/items, we found a five‐factor solution that explained 67% of the total variance. Inspection of items that composed each factor suggests five familiar constructs, with mental compulsions and reassurance‐seeking included with sexual, aggressive, and religious obsessions (unacceptable/taboo thoughts). Conclusions: This study suggests that the concept of the “pure obsessional” (e.g., patients with unacceptable/taboo thoughts yet no compulsions) may be a misnomer, as these obsessions were factorially associated with mental compulsions and reassurance‐seeking in these samples. These findings may have implications for DSM‐5 diagnostic criteria. Depression and Anxiety, 2011. © 2011 Wiley‐Liss, Inc.     

Piloting the perinatal obsessive-compulsive scale (POCS): development and validation

Onset/worsening of obsessive-compulsive disorder (OCD) during the perinatal period are frequently seen clinically. No specific tool assessing the unique content, context, severity, and onset of perinatal OCD exists. A self-report scale of perinatal obsessions and compulsions, the Perinatal Obsessive-Compulsive Scale (POCS), was developed and validated. A total of 162 women (67 pregnant, 95 postpartum) participated in this pilot study. They completed the POCS as well as the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). The POCS has good construct validity, reflected by representative items, high internal consistency, good concurrent validity and discriminative capacity. The most common obsessions were fear of having an unhealthy baby at birth, contamination, the baby being taken away, and infant death. Behavioral compulsions such as repeating rituals, asking for reassurance, checking, and cleaning mirrored these obsessions. The POCS helps clinicians detect perinatal OCD while giving perinatal women an opportunity to openly discuss socially sensitive issues.     

Quality of life in OCD: differential impact of obsessions, compulsions, and depression comorbidity.

OBJECTIVE: An anxiety disorder severely affects the sufferer's quality of life (QOL), and this may be particularly true of those with obsessive-compulsive disorder (OCD). This study examines the differential impact of obsessions, compulsions, and depression comorbidity on the QOL of individuals with OCD. METHOD: Forty-three individuals diagnosed with OCD according to DSM-IV criteria and experiencing clinically significant obsessions and compulsions completed measures of QOL, obsessive-compulsive symptom severity, and depression severity. RESULTS: Obsession severity was found to significantly predict patient QOL, whereas the severity of compulsive rituals did not impact on QOL ratings. Comorbid depression severity was the single greatest predictor of poor QOL, accounting for 54% of the variance. CONCLUSIONS: Given the importance of these symptoms, treatments that directly target obsessions and secondary depression symptoms in OCD are warranted. However, replication of these findings in a prospective cohort study is required, because although the the current study's cross-sectional design allows for the examination of the associations among obsessions, depression, and QOL, it cannot establish their temporal framework (that is, causal relations).     

Obsessive-compulsive disorder symptom dimensions show specific relationships to psychiatric comorbidity

The goals of this study were to examine relationships among symptom categories in obsessive-compulsive disorder (OCD), to establish OCD symptom dimensions by factor- and cluster-analytic analyses, and to explore associations between OCD symptom dimensions and comorbid neuropsychiatric conditions. A total of 317 OCD participants underwent a systematic diagnostic interview using the Structured Clinical Interview for DSM-IV. OCD symptoms assessed by the Yale-Brown Obsessive-Compulsive Scale Symptom Checklist (N=169) and by the Thoughts and Behaviors Inventory (N=275) were subjected to factor and cluster analyses. An identical four-factor solution emerged in two different data sets from overlapping samples, in agreement with most smaller factor-analytic studies employing the YBOCS checklist alone. The cluster analysis confirmed the four-factor solution and provided additional information on the similarity among OCD symptom categories at five different levels. OCD symptom dimensions showed specific relationships to comorbid psychiatric disorders: Factor I (aggressive, sexual, religious and somatic obsessions, and checking compulsions) was broadly associated with comorbid anxiety disorders and depression; Factor II (obsessions of symmetry, and repeating, counting and ordering/arranging compulsions) with bipolar disorders and panic disorder/agoraphobia; and Factor III (contamination obsessions and cleaning compulsions) with eating disorders. Factors I and II were associated with early onset OCD. This study encourages the use of cluster analyses as a supplementary method to factor analyses to establish psychiatric symptom dimensions. The frequent co-occurrence of OCD with other psychiatric disorders and the relatively specific association patterns between OCD symptom dimensions and comorbid disorders support the importance of OCD subtyping for treatment, genetic, and other research studies of this heterogeneous disorder.     

Assessment of severity and change in obsessive compulsive disorder.

Useful clinician-rated measures of OCD are now available. The Y-BOCS and NIMH Global OC both seem suitable for monitoring outcome in drug trials of OCD. These two scales seem relatively specific for symptoms of OCD and are sensitive to drug-induced changes in symptoms. Neither the Y-BOCS nor the NIMH Global OC confuse trait with state. There are ample data suggesting that the Y-BOCS is reliable and valid scale. Unlike some of the symptom inventories, such as the LOI and MOCI, final scores on the NIMH Global OC and Y-BOCS are not influenced directly by the type or number of obsessions and compulsions present. A computer-administered version of the Y-BOCS has been developed. Currently available patient-rated instruments suffer from serious shortcomings, including insensitivity to change and poor representation of patients with mono-symptomatic clinical pictures (e.g., hoarding alone). Some rating scales have been adapted for use in children with OCD. Several groups, including our own, have elected to use change scores on the 10-item Y-BOCS and a global measure of OCD, such as the NIMH Global OC or modified OGI, as the principal outcome variables in drug trials in patients with OCD. Several studies have selected a 35% decrease in Y-BOCS scores from baseline as indicative of clinically significant improvement. A limitation of all single-item global measures is that they cannot be resolved into smaller components. The more fine-grained analysis that is possible with the multi-item Y-BOCS makes it more desirable as a primary outcome measure, with a global scale as a secondary outcome measure.     

Symptom correspondence between clinicians and patients on the Yale–Brown Obsessive Compulsive Scale

The present study examined concordance between the Yale–Brown Obsessive–Compulsive Scale (Y-BOCS) and its self-report version (Y-BOCS-SR), as well as theoretically derived moderators. Sixty-seven adults (ages 18–67) with obsessive–compulsive disorder (OCD) were administered the Y-BOCS prior to completing self-report measures. The Y-BOCS-SR generated lower scores relative to the clinician-administered Y-BOCS (5.3 points lower). Strong correspondence was shown between the Y-BOCS and Y-BOCS-SR; however, many items exhibited fair to moderate agreement, particularly the resistance and control against obsessions/compulsions items. Depression significantly moderated correspondence such that Y-BOCS-SR scores significantly predicted Y-BOCS scores in the presence of low and average depression levels in our sample, but not for patients with high levels of depression relative to the rest of our sample; gender, generalized anxiety and obsessionality did not significantly impact agreement. Synthesizing the present data, the Y-BOCS-SR demonstrates modest agreement with the Y-BOCS and may underestimate clinical severity especially for those with high levels of depression.     

Convergent and discriminant validity of the Children's Yale-Brown Obsessive Compulsive Scale-Symptom Checklist

The Children's Yale-Brown Obsessive Compulsive Scale-Symptom Checklist (CY-BOCS-SC; Scahill, L., Riddle, M. A., McSwiggin-Hardin, M., Ort, S. I., King, R. A., Goodman, W. K., et al. (1997). Children's Yale-Brown Obsessive Compulsive Scale: Reliability and validity. Journal of the American Academy of Child and Adolescent Psychiatry, 36, 844-852) is widely used to assess the presence of obsessions and compulsions in youth. Although factor analytic studies have established symptom dimensions of the CY-BOCS-SC, little is known of its psychometric properties. The present study sought to examine the convergent and discriminant validity of the CY-BOCS-SC. Eighty-six youth with obsessive compulsive disorder (OCD) and their parents were administered the CY-BOCS-SC, the CY-BOCS severity items, and the Anxiety Disorders Interview Schedule for DSM-IV: Parent Version (ADIS-IV-P). Children completed the Children's Depression Inventory and Multidimensional Anxiety Scale for Children. Internal consistency of CY-BOCS-SC symptom dimensions ranged from poor to good. The CY-BOCS-SC demonstrated good to excellent convergent validity, as demonstrated by large correlations with conceptually similar items on the ADIS-IV-P. The discriminant validity of the CY-BOCS-SC was also good, as evidenced by small, generally non-significant, correlations between the CY-BOCS-SC dimensions and depressive and anxiety symptoms, OCD symptom severity, and trichotillomania symptoms. These results provide initial psychometric support for the CY-BOCS-SC and support its use as a clinical and research instrument for assessing presence of a range of obsessive and compulsive symptoms in youth with OCD.     

The relationship between types and severity of repetitive behaviors in Gilles de la Tourette's disorder and obsessive-compulsive disorder

BACKGROUND: This study investigated which categories of obsessive-compulsive and Tourette-related behaviors in Gilles de la Tourette's disorder and obsessive-compulsive disorder (OCD) without tics are experienced as most severe across the study groups and what the differences are in symptom distribution between the study groups. METHOD: Fourteen subjects with both Tourette's disorder and OCD, 18 subjects with Tourette's only, 21 subjects with OCD (no tics), and 29 control subjects were studied using a semistructured interview designed to equally assess Tourette- and OCD-related behaviors according to DSM-III-R criteria. Each reported repetitive behavior was evaluated on the presence of anxiety and on goal-directedness. Anxiety-related items were categorized as obsessions or compulsions and non-anxiety-related items as impulsions. Severity of each reported item was assessed with respect to time per day consumed and amount of distress and interference induced by the item. Following these criteria, each reported item was classified as a symptom, a subthreshold symptom, or just as being present. RESULTS: Across the study groups, obsessions were experienced as more severe than (Tourette-related) impulsions and compulsions. Within the study groups, patients with both Tourette's disorder and OCD reported more symptomatic Tourette-related impulsions, such as mental play, echophenomena, and impulsive or self-injurious behaviors; less overall symptomatic obsessions; and less symptomatic washing than patients with OCD (no tics). The differences among individuals with Tourette's with or without OCD reflected differences in symptom severity rather than differences in symptom distribution. CONCLUSION: Obsessions are more time consuming, distressing, and interfering than compulsions and impulsions. Furthermore, the symptomatic repetitive behaviors were distributed differently among patients with both Tourette's disorder and OCD and patients with OCD (no tics). Patients with Tourette's and OCD are phenomenologically more similar to Tourette's than to OCD. These differences possibly represent differences in underlying pathophysiology between Tourette's and tic-free OCD.     

Schizo-obsessive and obsessive-compulsive disorder: comparison of clinical characteristics and neurological soft signs

The purpose of the study was to examine whether schizophrenia with obsessive-compulsive disorder (OCD) represents a severe form of OCD-spectrum disorders on the basis of neurological soft signs (NSS) and obsessive-compulsive (OC) symptoms. Sixteen patients with OCD-schizophrenia, 25 OCD patients and 23 healthy controls (HC) were studied. Scales for the Assessment of Positive (SAPS) and Negative Symptoms (SANS), Clinical Global Impressions Scale and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) were used to assess the schizophrenic and OC symptomatology. NSS were evaluated with the Neurological Evaluation Scale (NES). OCD-schizophrenics had significantly higher scores on total NES than HC. The patients with OCD were more likely to have total Y-BOCS and subscale scores of compulsions than patients with OCD-schizophrenia. The rate of symmetry obsessions and cleaning/washing compulsions were significantly higher in patients with OCD compared to OCD-schizophrenics. We have found no correlation of OC symptoms with schizophrenic symptomatology. Our findings may suggest that OCD-schizophrenia is a distinct subtype of schizophrenia, not a more severe form of OCD-spectrum disorder.     

Clinical investigation of the ICD-10 subcategories for obsessive-compulsive disorder

Abstract  To examine the validity of ICD-10 subcategories for obsessive-compulsive disorder (OCD), the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) was applied to 53 OCD patients. The ratios of Y-BOCS compulsions subscore to obsessions subscore were calculated. The group with ratios around one consisted of patients diagnosed in three subcategories (F42.0, F42.1 and F42.2). This suggests that subjective subcategorization such as ICD-10 may be inadequate to differentiate between predominantly obsessive and compulsive patients compared with differentiation by quantitative assessment such as the Y-BOCS ratio. Thus, in selecting the appropriate therapeutic methods, we emphasize the usefulness of quantitative assessment in clinical settings.     

Overvalued ideation as a predictor of fluvoxamine response in patients with obsessive-compulsive disorder

The presence of overvalued ideation (OVI) in patients with obsessive-compulsive disorder (OCD) has been theoretically linked to poorer treatment outcome. OVI has recently been shown to predict treatment outcome in OCD. The purpose of the present study is to determine whether OVI predicts medication treatment response, controlling for initial symptom severity and measurement error. The sample consisted of 34 outpatients diagnosed with OCD who completed an open-label clinical trial of fluvoxamine of 10 weeks' duration. Clinicians administered the Overvalued Ideas Scale (OVIS) at baseline. Symptom severity was rated at baseline and at the end of week 10 using the Yale-Brown Obsessive-Compulsive Scale. Of those who completed the trial, 68% showed a reliable change in obsessions and 62% showed a reliable change in compulsions. Analysis of variance showed that baseline OVIS predicted outcome for obsessions, but not compulsions. A key limitation was the relatively low number of individuals in the upper quartile on the OVIS, thus reducing the predictive power of the measure in relation to treatment outcome. Future research should examine medication treatment outcome with higher scoring patients.