The long-term clinical effects of pipotiazine palmitate were tested in 206 men and women who were either not responding well to their previous neuroleptic therapy or who were negligent about pursuing protracted oral drug therapy. Of the 206 patients, 130 were suffering from some form of chronic schizophrenia; the remainder presented with depression, psychoneurotic or behavioural disorders. Pipotiazine palmitate, a long-acting depot neuroleptic, was given as a monthly intramuscular injection for up to 23 months. The average starting dose was 50 mg/injection and the average final dose was 65 mg/injection. These doses were somewhat lower than those usually reported in the literature, however all but a few patients received oral neuroleptics or antidepressants concomitantly. Psychiatric testing using the Brief Psychiatric Rating Scale revealed that significant improvement was achieved over time in all diagnostic groups represented. Individual as well as cumulative scores improved steadily for 6 momths at which time symptomatology was minimal in most patients. Pipotiazine palmitate was well tolerated, and only seven (3.4%) of the 206 patients had to interrupt therapy because of unwanted effects. The most frequent side-effects were extrapyramidal symptoms, particularly tremor and rigidity, yet these effects led to the discontinuation of therapy in only five patients.