After screening titles and abstracts, 29 full-text articles were reviewed, of which 20 were excluded for the following reasons: (i) four studies were systematic reviews or meta-analyses on G-protein function [6,11,18,19]; (ii) seven studies assessed SNP effects in other psychiatric disorders [20–26]; (iii) three studies did not use a case-control design [27–29]; (iv) three studies did not assess GNβ3 C825T but measured G-protein expression [5,30,31]; and (v) three studies assessed GNβ3 C825T and the antidepressant response [16,32,33]. The gene discussed is GNB3; the disease is psychiatric disorder.