Clozapine therapy in refractory affective disorders: polarity predicts response in long-term follow-up

To determine the efficacy and tolerance of long-term clozapine therapy in refractory affective illness.

Hospital records were reviewed for 193 treatment-resistant patients with a discharge diagnosis of bipolar disorder (N = 52), schizoaffective disorder (N = 81), unipolar depression (N = 14), schizophrenia (N = 40), or other disorders (N = 6) started on clozapine therapy as inpatients at McLean Hospital. An independent "best-estimate" diagnosis, based on DSM-III-R criteria, was established for each patient. Patients were contacted at least 6 months after clozapine initiation for structured follow-up interviews by raters blind to diagnosis. Patients were stratified by diagnosis, and a variety of patient characteristics and outcome measures were compared.

Subjects were followed up a mean of 18.7 months after clozapine initiation. Bipolar manic and schizoaffective bipolar subjects had significantly better outcomes than unipolar, bipolar, and schizoaffective depressed patients on a variety of measures. One or more episodes of depression prior to clozapine predicted clozapine discontinuation (p = .01). Affective and schizoaffective subjects had baseline measures of social functioning similar to that of the schizophrenics but had significantly greater improvement in scores at follow-up.

Clozapine is an efficacious and well-tolerated therapy for refractory affective illness. Manic symptomatology predicts a more favorable response than depression.