Major depression among methamphetamine users entering drug treatment programs.

Objective: To determine the prevalence of major depression among people entering treatment for methamphetamine use.

Design, Setting And Participants: The study was a cross-sectional survey involving 41 specialised drug and alcohol treatment agencies in Brisbane and Sydney. Services provided by these agencies included residential rehabilitation, detoxification and counselling. Participants were 400 people entering treatment for methamphetamine use who were recruited from participating treatment agencies between January 2006 and November 2007. Participants underwent a structured, face-to-face, 1.5-hour interview. Assessment instruments included the Composite International Diagnostic Interview and the Short Form 12.

Main Outcome Measure: Diagnosis of a major depressive episode in the year prior to the study.

Results: The prevalence of major depression in the year prior to the study was 40% (95% CI, 35%-44%). A noteworthy post-hoc observation was that a further 44% of participants met the symptom criteria for major depression but were excluded from a diagnosis because their symptoms were better accounted for by psychoactive substance use. Both major depression and these latter cases of "substance-induced depression" were associated with severe symptoms of depression, high levels of disability and suicidal ideation.

Conclusion: Most people entering treatment programs for methamphetamine use have levels of depression that require clinical management. Making a diagnosis of major depression in the context of heavy methamphetamine use is problematic because of substance-induced symptoms of depression.