Objective: Depot antipsychotic medication is often prescribed as maintenance treatment for patients with bipolar affective disorder. In this study we examined the case notes of 14 patients with bipolar disorder who had been prescribed depot antipsychotics. Our aim was to establish the effectiveness of depot medication in this group.

Method: We calculated the total number of hospital admissions, length of hospital stay, and total number of affective episodes for each patient from the onset of their illness to the time of the study. The frequency of affective episodes and hospital admission were compared during periods on or off depot medication.

Results: Treatment with depot antipsychotics was associated with a significant decrease in the number of hospital admissions, overall affective episodes and manic episodes in particular.

Conclusions: Prophylactic treatment with depot antipsychotics may be useful for certain patients with bipolar disorder, in particular those patients who experience frequent manic episodes. Further proof of the efficacy of depot antipsychotics in the prophylaxis of bipolar affective disorder requires the completion of a double-blind prospective trial.