The duration of maintenance therapy in chronic schizophrenia.

The incidence of relapse was compared between two groups of chronic schizophrenic patients (mean duration periods 19 months and 29.5 months) discontinuing depot neuroleptic injections, and matched controls remaining on depot injections. The results show a higher relapse rate in patients discontinuing injections, significant at the 1% level, in both groups. The proportion of patients improving upon resumption of depot injections confirms the importance of this form of medication in comparison to prescribed oral medication. The results strongly suggest that there is a significant therapeutic gain in continuing maintenance therapy with depot neuroleptic injections for a minimum period of 3 years after the last relapse in a substantial proportion of chronic schizophrenic patients.