Meta analysis on the efficacy of pharmacotherapy versus placebo on anorexia nervosa

BACKGROUND: Anorexia Nervosa (AN) has a devastating impact on the psychological and physical well being of affected individuals. There is an extensive body of literature on interventions in AN, however more studies are needed to establish which form of pharmacotherapy is effective. The few meta-analyses that have been done are based on one type of medication only. This article is the first to present data on three different, most commonly used, forms of pharmacotherapy. The primary objective of this meta-analysis was to create an overview and to determine the efficacy of three forms of pharmacotherapy (antidepressants, antipsychotics, hormonal therapy) compared to treatment with placebo in patients with AN. METHOD: A systematic literature search was performed to identify all randomized controlled intervention trials investigating the effectiveness of pharmacotherapy for AN within the following databases: PubMed, PsycINFO, Embase and Cochrane Library. In addition, 32 relevant reviews and meta-analyses were screened for additional intervention studies. A meta-analysis was performed on a total of 18 included studies (N = 869). Efficacy was measured in terms of weight gain or weight restoration. RESULTS: The pooled effect sizes indicating the difference between antidepressants and placebo, and between antipsychotics and placebo on weight were not significant. Because of the small sample size no meta regression and subgroup analyses could be conducted. The pooled effect size indicating the difference between hormonal therapy and the placebo condition on weight (all weight measures) at post-treatment was 0.42 (95% CI: 0.11 ~ 0.73), which was significant. For hormonal therapy heterogeneity was high (I(2) = 64.70). No evidence for publication bias was found. Meta-regression analyses of the weeks of medication treatment (slope = −0.008) yielded a significant effect (p = 0.04). CONCLUSIONS: In this study we found that hormonal therapy has a significantly larger effect on weight compared to placebo in the treatment of AN. However for these analyses heterogeneity was high, which means that these results have to be regarded with caution. We found that anti-depressants and antipsychotics had no significant effect on weight compared to placebo in the treatment of AN, although the power to detect significant effects was too low. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40337-014-0027-x) contains supplementary material, which is available to authorized users.