Several GWA studies of personality and temperament have been published assessing Neuroticism (49–51), five personality traits from the NEO Personality Inventory (NEO-PI; 52), and four temperaments from Cloninger’s Tridimensional Personality Questionnaire (TPQ; 53). Despite the large samples employed in these studies, no GW significant associations were observed, and few associations had p values <10−6. Several genes of potential interest were identified, including associations between MAMDC1 and PDE4D and Neuroticism (49–50). None of the top SNPs or genes in our study of the TEMPS-A corresponded with the top SNPs in these studies, nor were any of the top SNPs in those studies even nominally significant (p<0.05) in our data. All of these earlier GWA studies of personality and temperament were performed using population-based samples. Unlike the NEO-PI and TPQ, which were developed to assess aspects of personality in the general population, the TEMPS-A was specifically designed to quantify temperament in the context of bipolar symptomatology (24,25). It is thus possible that the sole use of BDI cases in our analyses provided increased power for the detection of genes associated with variation in temperament compared with other studies.
