“…Known EFs associated with BD can be grouped into three categories based on developmental timing; prenatal (e.g., infection during pregnancy, Vitamin D levels); childhood (e.g., maltreatment, parental loss), and adolescence/adulthood (e.g., cannabis and stressful life events) [ 12 , 16 , 17 ]. While GxE have been investigated on a genome-wide scale in genome-wide gene–environment interaction studies for a number of psychiatric phenotypes [ 18 , 19 , 20 , 21 , 22 , 23 ], studies of GxE in BD have, with a few exceptions, been limited to candidate gene approaches (e.g. : variation in BDNF , stressful life event, and worst episodes of depression and mania [ 24 ], childhood trauma and age of BD onset, severity, and chronicity [ 25 ]) and a handful of other GxE associations [ 26 , 27 , 28 , 29 , 30 , 31 ]—recently reviewed by Misiak et al [ 32 ] and Musci et al [ 33 ]).…”