Ten years' experience with clozapine in treatment-resistant schizophrenic patients:: factors indicating the therapeutic response

A prospective study in treatment-resistant schizophrenic patients was performed over 10 years to evaluate the therapeutic response to clozapine and the variables related to this treatment. Eighty schizophrenic and schizoaffective patients (according to Diagnostic and Statistical Manual [DSM]-IIIR criteria), considered as refractory (previously resistant to at least two different typical neuroleptics), were studied. The average dose of clozapine was 267 mg/d. The clinical variables considered were. Brief Psychiatric Rating Scale (BPRS), number of admissions before and after clozapine treatment and the Strauss-Carpenter scale as measures of efficacy; Premorbid Adjustment Scale (PAS), to assess personal and social adjustment before illness; Karolinska Personality Scale (KPS) to assess stable traits of personality; and the Simpson-Angus scale as a measure of extrapyramidal symptoms. Sixty percent of patients showed a significant improvement after clozapine treatment. Side-effects were mild and well tolerated, with no cases of haematological disturbance and only five withdrawals because of adverse events. The severity of the episode, according to BPRS score and anxiety as a personal trait, are related to good prognosis. Other relationships between improvement and clinical and demographic variables are discussed.