Initial 2008 findings [12] that substance use disorders were not important predictors of incident mood and anxiety disorders may have resulted from the broad categories examined. More refined measures of severity and more specific substance categories provided informative results about incident mood and anxiety disorders, suggesting utility in applying similar methods to additional substances. The consistency in two studies that mood disorders predict incident substance use (opioids used nonmedically, and a combined substance category) suggests further studies to understand this relationship better. Psychopathological predictors of incident adolescent drug use have been studied extensively, but less is known about these predictors in young and middle-aged adults. Finally, the findings that wave 1 substance use disorders did not predict the persistence of depressive or anxiety disorders at wave 2 may indicate that substance disorders are not important to the course of affective or anxiety disorders, but may also indicate that additional information about the time-varying course of the substance disorders during the follow-up needs to be taken into account. Finally, the inverse relationships between wave 1 overweight/ obesity and incident substance use
