Weight changes in people with early psychosis treated with oral or long-acting injectable aripiprazole

Weight gain remains a major problem in young people with psychosis treated with antipsychotic medication. Aripiprazole is now available in monthly long-acting injection (LAI) and daily oral tablet formulation, but information is lacking about differences in weight gain between the two formulations. We monitored for up to 24 months the weight changes associated with oral or LAI-administered aripiprazole and in a group who not prescribed any antipsychotic medication.

Participants included 109 young people with early psychosis (n = 30 Oral, 41 LAI, 38 Nil antipsychotic) with a treatment completion median time of 15 months. Weight (kilogram) and body mass index (BMI) were recorded at 3 monthly intervals. Multilevel modelling analyses assessed the contribution of time and group on weight change.

Participants taking nil antipsychotics did not gain weight over time, while the two aripiprazole groups gained a combined average of 7.1 kg (SD = 5.0) or 1.9 BMI (SD = 0.4). An examination of formulation effects showed a significantly greater rate of change over time in the Oral group with a weight increase of approximately 11.0 kg (SD = 8.2) or 3.5 BMI (SD = 0.7, compared to the LAI group with a gain of 3.7 kg (SD = 2.1) or 0.8 BMI (SD = 0.1) in the LAI group. These differences could not be explained by demographic or clinical characteristics, medication dosage, or baseline weight.

While aripiprazole is generally considered relatively benign in terms of weight, it still poses a significant risk especially for people with early psychosis. However the current study suggests that the risk may be lower in those treated with LAI than with Oral formulation, consolidating the clinical utility of LAI.