The injection of fluphenazine decanoate, a new long acting antipsychotic drug, resulted in rapid improvement in 9 of 12 chronic schizophrenic patients. The length of response following a single injection ranged from 7-39 days, with a mean length of activity of 16-22 days. This drug promises to be useful in the treatment of psychosis for economic reasons as well as its rapid action, its efficacy and its long action.Abstract Teaser