<b>Conclusion:</b> This study provides the first evidence of abnormalities of <i>PVALB</i> promoter methylation in MDD and its correlation with MDD severity indicating a role for epigenetics in this psychiatric disorder.
We examined whether a model positing two latent factors, internalizing and externalizing, explained the interrelationships among six psychiatric disorders (major depressive disorder, generalized anxiety disorder, separation anxiety disorder, attention-deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder) in adolescents, and whether there are common genetic and environmental influences on internalizing and externalizing latent factors.