Pharmacogenetic Associations of Antipsychotic Drug-Related Weight Gain: A Systematic Review and Meta-analysis

Although weight gain is a serious but variable adverse effect of antipsychotics that has genetic underpinnings, a comprehensive meta-analysis of pharmacogenetics of antipsychotic-related weight gain is missing. In this review, random effects meta-analyses were conducted for dominant and recessive models on associations of specific single nucleotide polymorphisms (SNP) with prospectively assessed antipsychotic-related weight or body mass index (BMI) changes (primary outcome), or categorical increases in weight or BMI (≥7%; secondary outcome). Published studies, identified via systematic database search (last search: December 31, 2014), plus 3 additional cohorts, including 222 antipsychotic-naïve youth, and 81 and 141 first-episode schizophrenia adults, each with patient-level data at 3 or 4 months treatment, were meta-analyzed. Altogether, 72 articles reporting on 46 non-duplicated samples ( n = 6700, mean follow-up = 25.1wk) with 38 SNPs from 20 genes/genomic regions were meta-analyzed (for each meta-analysis, studies = 2–20, n = 81–2082). Eleven SNPs from 8 genes were significantly associated with weight or BMI change, and 4 SNPs from 2 genes were significantly associated with categorical weight or BMI increase. Combined, 13 SNPs from 9 genes (Adrenoceptor Alpha-2A [ ADRA2A ], Adrenoceptor Beta 3 [ ADRB3 ], Brain-Derived Neurotrophic Factor [ BDNF ], Dopamine Receptor D2 [ DRD2 ], Guanine Nucleotide Binding Protein [ GNB3 ], 5-Hydroxytryptamine (Serotonin) Receptor 2C [ HTR2C ], Insulin-induced gene 2 [ INSIG2 ], Melanocortin-4 Receptor [ MC4R ], and Synaptosomal-associated protein, 25kDa [ SNAP25 ]) were significantly associated with antipsychotic-related weight gain ( P -values < .05–.001). SNPs in ADRA2A , DRD2 , HTR2C , and MC4R had the largest effect sizes (Hedges’ g ’s = 0.30–0.80, ORs = 1.47–1.96). Less prior antipsychotic exposure (pediatric or first episode patients) and short follow-up (1–2 mo) were associated with larger effect sizes. Individual antipsychotics did not significantly moderate effect sizes. In conclusion, antipsychotic-related weight gain is polygenic and associated with specific genetic variants, especially in genes coding for antipsychotic pharmacodynamic targets.