Among environmental factors, maternal rule inconsistency and childhood trauma were associated with all comorbidity classes while lack of paternal and maternal closeness was most strongly associated with the SUD-CD class (although the estimates included 1). The association between maternal rule inconsistency and vulnerability for all classes of psychopathology is partly supported by our previous reports that this parenting behavior is a risk factor for offspring nicotine dependence (Scherrer et al., 2012), but is not in line with our earlier report of no association between maternal rule inconsistency and offspring marijuana abuse/dependence (Scherrer et al., 2008). These inconsistent results may reflect the limitation to using a single measure of psychopathology as an outcome. The association between familial risk factors and substance use disorders may best be modeled by considering comorbidity in the outcome. The association between parental closeness and SUD is consistent with evidence of a protective association between parental emotional warmth and externalizing behaviors (Sentse et al., 2009). Additional research is warranted to clarify the independent association between specific parenting behaviors and offspring psychopathology as these offspring age through the period of risk for each type of psychopathology.
