Emergence of obsessive compulsive symptoms during treatment with clozapine.

BACKGROUND: Clozapine differs from other currently available antipsychotics in its prominent serotonin blockade. We explore the relationship between clozapine and obsessive compulsive symptoms, which have been linked to deficient serotonin. METHOD: We reviewed our experience in treating 49 chronic schizophrenic patients with clozapine. RESULTS: Five patients were identified who experienced either de novo obsessive compulsive symptoms or exacerbation of preexistent symptoms. Clinical details are provided for each case. CONCLUSION: Clozapine may produce or unmask obsessive compulsive symptoms. This may reflect a variation on the normal course of clinical improvement, or may more specifically result from clozapine's atypical pattern of CNS receptor antagonism. Further attention to this issue is warranted.