Reducing the dose of depot neuroleptics in stable schizophrenia.

In order to determine the safety of reducing maintenance neuroleptic dose in long-term ambulatory schizophrenia, a step-wise depot reduction study was carried out on patients over a six month period. Doses were reduced by 1/8 of original approximately every two months for a total of three reductions. At the end of dose reduction and at six month follow-up, relapse rate was calculated. Relapse in this study was defined as the clinical decision to either increase neuroleptic dose or to hospitalize. Approximately 50% of the patients relapsed. There was no association with life events as measured by the Paykel scale. Where relapse occurred, it was usually seen subsequent to the second dose reduction. Patients who survived dose reduction had been maintained for a significantly longer period on depot neuroleptics and tended to suffer from a form of schizophrenia which required the co-administration of antidepressants. The findings show that, for a population on long-term depot medication, the risk of symptom exacerbation after gradual step-wise neuroleptic reduction is 50%. The results help to delineate which patients will fall into that 50%.