Weight gain and prolactin levels in patients on long-term antipsychotic medication: a double-blind comparative trial of haloperidol decanoate and fluphenazine decanoate.

A one year double-blind trial of haloperidol decanoate and fluphenazine decanoate was conducted in nineteen out-patients who had previously received at least one year's treatment with fluphenazine decanoate and were already overweight, as judged by a Body Mass Index of 25+. Although the difference was not statistically significant, patients treated with haloperidol decanoate showed a trend to less weight gain than patients who continued on fluphenazine decanoate, even though the haloperidol to fluphenazine dose ratio was 4:1. No statistically significant changes in mental state were observed and the incidence of extrapyramidal side-effects in the two treatment groups was similar.