Obsessive compulsive symptoms in patients with Schizophrenia on Clozapine and with Obsessive Compulsive disorder: a comparison study.

Obsessive compulsive symptoms are commonly reported in those with schizophrenia. Clozapine has previously been reported to induce, aggravate and alleviate these symptoms. It is unclear if these are similar to the symptoms experienced by those with obsessive compulsive disorder. This study describes the obsessive compulsive symptom profile of a population of patients with schizophrenia treated with clozapine (n = 62) and compares this with patients with Obsessive Compulsive Disorder (n = 35). All participants were attending an outpatient community mental health service. The Obsessive Compulsive Inventory (which measures the frequency and associated distress of a range of "behavioural" and "cognitive" symptoms), the Hospital Anxiety and Depression Scale and a demographic questionnaire were completed. In addition the schizophrenia group treated with clozapine completed the Brief Psychiatric Rating Scale. The OCD group reported significantly more symptoms for all OCI subscales compared to the clozapine group. Overall fourteen (22%) of the schizophrenia treated with clozapine group had clinically significant total OCI scores. Two (3%) had documented OCS pre clozapine. De novo OCS was reported in twelve (19%) cases. Nine (11%) had documented OC symptoms pre-clozapine while only two (3%) had symptoms after clozapine was initiated. In terms of OC symptom profile, the clozapine group scored highest on the Doubting scale, a cognitive symptom whereas the OCD group scored highest on Washing, a behavioural symptom. Both groups reported greater distress with cognitive rather than behavioural symptoms. Medication including clozapine dose was not correlated with symptom severity. Anxiety correlated highly with obsessive compulsive symptoms in the Clozapine group but not the OCD group. Within the Clozapine group, Obsessing correlated highly with Unusual Thought Content. Findings suggest that obsessive compulsive symptoms in the Clozapine group may reflect a subtype of 'schizo-obsessive' disorder.