Discriminating between substance-induced and independent depressive episodes in alcohol dependent patients

Objective: The purpose of this study is to examine the accuracy with which the depressive episodes of alcoholics undergoing treatment are classified as substance-induced depression (SID) or independent major depressive disorder (MDD). Method: Participants were 95 patients (64 men) undergoing partial hospital treatment for alcohol dependence. Affective disorders were assessed at baseline and 6 weeks, 3 months, 6 months and 12 months later. Results: Over one quarter of the depressive episodes originally diagnosed as SID were reclassified as MDD during the 1-year follow-up, due to a continuation of the depressive episode despite a period of prolonged abstinence from alcohol and drugs. Both history of MDD and lower levels of alcohol dependence were associated with diagnostic change from SID to MDD. Conclusions: These findings support the diagnostic complexity of these two types of depressive disorders and point to clinical features that may differentiate them.