Depression may either pre-exist and exacerbate cocaine dependence (“independent depression”), or be a sequela of cocaine-related psychobiological dysregulation (“substance induced depression”) (Leventhal et al., 2006). Cocaine dependent persons also may have trouble with emotion regulation soon after abstinence (Fox et al., 2007), and often are depressed when entering treatment (Carroll et al., 2003). Thus, depression may lead cocaine dependent individuals to seek or be referred for cocaine dependence treatment even though it does not necessarily increase the severity of the dependence per se. Correspondingly, pharmacotherapy for depression may reduce potential contributing factors to cocaine use (e.g., craving ,euphoria), but it has not been shown to reduce cocaine use (Nunes et al., 1995; Schmitz et al., 2001; Ziedonis and Kosten, 1991). Whether depression increases the risk of cocaine dependence, as has been shown for alcohol dependence (Kuo et al., 2006), remains to be investigated.
