Atypical antipsychotic use does not impact weight gain for individuals with extreme anorexia nervosa: a retrospective case-control study.

Background: There are no U.S. Food and Drug Administration (FDA)-approved medications for the treatment of anorexia nervosa (AN). Various medication classes have been evaluated for benefits in this population, including antipsychotics. Studies focused on use of antipsychotics for assistance with weight restoration in AN produced conflicting results. While current evidence does not suggest that antipsychotic medications can be generally recommended for persons with AN, some individuals might benefit from an antipsychotic medication for anxiety, mood, and the cognitive distortions that accompany the illness. It is well-established that atypical antipsychotics can cause weight gain when taken by other psychiatric populations. This published data can understandably limit the willingness of persons with AN to trial these medications. Given the conflicting results of studies examining antipsychotic-related weight gain in AN, it is currently hypothesized that individuals with extreme anorexia nervosa, restricting type, do not experience the weight gain seen in other psychiatric populations utilizing atypical antipsychotics.

Methods: Two hundred seventy-six individuals with extreme AN were enrolled in this retrospective, case-control study between April 1, 2016 and June 30, 2022 utilizing study-specific inclusion and exclusion criteria. Clinical and demographic data, including use of atypical antipsychotics and weights, were retrospectively obtained from chart review. Variables were assessed for normality using univariate statistics. Continuous variables were described using means (M) and standard deviations (SD) or medians and interquartile ranges (IQR) based on normality. Differences in weight gain between cohorts was ascertained via independent samples t-test. P values of < 0.05 were considered statistically significant, and all analyses were completed using SAS Enterprise Guide software version 7.1 (SAS Institute, Cary, NC) and R version 4.3.1 (R Core Team, 2023).

Results: Use of antipsychotics in this population of individuals with extreme AN did not impact the rate of weight gain (M: 1.7 kg/week, SD: 0.9 and 0.8, for cases and controls respectively).

Conclusions: Weight gain is often cited by individuals with AN as a feared side effect of antipsychotic medications. In this study, there was no difference in weight trends for individuals taking atypical antipsychotic medications during the refeeding process compared with individuals who were not.