Emergence of obsessive--compulsive symptoms and tics during clozapine withdrawal.

Treatment with clozapine may be associated with the appearance of obsessive-compulsive (OC) symptoms in up to 10% of schizophrenic patients. We present the first report of the emergence of de novo OC symptoms during clozapine withdrawal in two schizophrenic patients, associated in one with Tourette's syndrome-like tics. Resumption of clozapine led to the complete disappearance of the OC symptoms and a substantial alleviation of the tics. It is suggested that an imbalance between the dopamine and serotonin systems may account for this complication.