Furthermore, several oral hypoglycemic agents including biguanides (e.g., metformin), peroxisome proliferator-activated receptor-γ (PPAR- γ) agonists (e.g., rosiglitazone, pioglitazone), and glucagon-like peptide 1 receptor agonists (GLP1RA; e.g., liraglutide) have been tested as potential adjunctive therapies for depression (56). This evidence concerns the gene GLP1R and major depressive disorder.