Preferential Aggregation of Obsessive-Compulsive Spectrum Disorders in Schizophrenia Patients with Obsessive-Compulsive Disorder

Article excerpt

Objective: To validate a complex association between schizophrenia and obsessive-compulsive disorder (OCD).

Method: We used the Structured Clinical Interview for DSM-IV Axis I disorders to compare the rate of OCD spectrum and additional Axis I disorders in 100 patients who met criteria for both schizophrenia and OCD, non-OCD schizophrenia (n = 100), and OCD (n = 35).

Results: There was a robust between-group difference in the number of patients with one or more OCD spectrum disorders (schizo-obsessive n = 30, compared with schizophrenia n = 8; P = 0.001), that is, higher rates of body dysmorphic (8% compared with 0%) and tic (16% compared with 4%) disorders. No difference was revealed in affective, anxiety, and substance use disorders. We found comparable rates of OCD spectrum disorders in the schizo-obsessive and OCD groups (30% and 42.8%, respectively; P = 0.32).

Conclusion: Preferential aggregation of OCD spectrum disorders in the schizo-obsessive group supports this unique clinical association. Whether a schizo-obsessive interface represents comorbidity or a specific subtype of schizophrenia warrants further investigation.

(Can J Psychiatry 2006;51:746-754)

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Clinical Implications

* Compared with schizophrenia patients, patients with both schizophrenia and OCD exhibit higher rates of OCD spectrum disorders, primarily BDD and tic disorders.

* Because the presence of OCD spectrum disorders increases the odds of OCD in schizophrenia, targeting these additional syndromes may improve identification of an obsessive-compulsive component in schizophrenia.

* The complex association of schizophrenia and OCD should be considered in diagnostic procedures and treatment planning.

Limitations

* The identification of comorbid disorders may be hampered by the limited awareness of illness in schizophrenia patients.

* Since the SCID does not assess all possible OCD spectrum disorders and we excluded subsyndromal forms of the disorders, the data may undererepresent the rate of OCD spectrum comorbidity.

* The cross-sectional design of the study precludes evaluation of temporal interrelations between comorbid disorders.

Key Words: comorbidity, obsessive-compulsive spectrum, schizophrenia, obsessive-compulsive disorder

Abbreviations used in this article

ANOVA analysis of variance

BDD body dysmorphic disorder

CGI Clinical Global Impression scale

MDD major depressive disorder

OCD obsessive-compulsive disorder

OR odds ratio

SANS Schedule for the Assessment of Negative Symptoms

SD stanadard deviation

SAPS Schedule for the Assessment of Positive Symptoms

SCID Structured Clinical Interview for DSM-IV Axis-1 Disorders

SCID-IP Structured Clinical Interview for DSM-IV Axis-1 Disorders, Patient Edition

Y-BOCS Yale-Brown Obsessive Compulsive Scale

Identification of etiopathogenetic mechanisms of schizophrenia is hampered by a substantial phenotypic heterogeneity of the disorder. The concept of a schizo-obsessive disorder was suggested to delineate a relatively homogeneous subgroup of patients characterized by the presence of obsessive-compulsive symptoms or of OCD in addition to positive, negative, and disorganized symptoms of schizophrenia (1-3).

Although the identification of obsessive-compulsive symptoms in schizophrenia is challenging, data indicate that obsessions and compulsions can be identified as a separate dimension in patients with schizophrenia. Most recent reports point toward a substantial rate of OCD in schizophrenia (about 10% to 25%) that is revealed in both epidemiologic and clinical samples (4). OCD has also been detected across the lifespan in adolescent, adult, and elderly schizophrenia patients (5,6). Obsessive-compulsive symptoms in schizophrenia do not seem to be sequelae to chronic illness or neuroleptic treatment since a comparable rate of OCD (14%) has been noted in first-episode, predominantly drug-naive, schizophrenia patients (7). …