Comparison of clinical characteristics and comorbidity in schizophrenia patients with and without obsessive-compulsive disorder: schizophrenic and OC symptoms in schizophrenia.

Background: Since a substantial proportion of schizophrenia patients has symptoms of obsessive-compulsive disorder (OCD), we sought to provide a phenomenological characterization of a schizophrenia subgroup with OCD.

Method: A consecutive sample of patients who met DSM-IV criteria for both schizophrenia and OCD (N = 55) was compared with 55 schizophrenia patients without OCD matched for age and number of hospitalizations. Structured Clinical Interview for DSM-IV Axis I psychiatric disorders (SCID-I), including a specific module for tic disorders based on DSM-IV criteria, Scales for the Assessment of Positive and Negative Symptoms, Yale-Brown Obsessive-Compulsive Scale, Clinical Global Impressions scale, and Hamilton Rating Scale for Depression were used.

Results: Schizophrenia patients with OCD (N = 55) had lower positive dimension scores than schizophrenia patients without OCD (N = 55) (p =.01). Two subgroups of schizo-obsessive patients were identified: OCD independent of schizophrenia symptoms and OCD partially overlapping positive schizophrenia symptoms. Schizophrenia patients with OCD had more SCID-detectable OCD-spectrum disorder, primarily body dysmorphic disorder and chronic tic disorders. More schizophrenia patients with OCD were treated with either add-on serotonin reuptake inhibitors or clozapine.

Conclusion: Schizophrenia patients with OCD differ from their non-OCD-schizophrenia counterparts in severity of schizophrenia symptoms, co-occurrence of OCD-spectrum disorders, and pharmacotherapy. These findings and the identification of 2 subgroups of schizo-obsessive patients support the validity of this unique clinical entity and may facilitate the establishment of diagnostic criteria for a schizo-obsessive subtype of schizophrenia.