The impact of mood symptomatology on pattern of substance use among homeless.

BACKGROUND: Homeless individuals are an extremely vulnerable and underserved population characterized by overlapping problems of mental illness and substance use. Given the fact that mood disorders are frequently associated with substance use disorders, we wanted to further highlight the role of excitement in substance abuse. Patterns of substance abuse among homeless suffering from unipolar and bipolar depression were compared. The "self-medication hypothesis" which would predict no-differences in substance preference by unipolar (UP) and bipolar (BP) depressed homeless was tested.

METHODS: Homeless individuals from the Vancouver At Home/Chez Soi study were selected for lifetime UP and lifetime BP depression and patterns of substances abused in the previous 12 months were identified with the Mini-International Neuropsychiatric Interview. Differences in substance use between BP-depressed homeless and UP-depressed homeless were tested using Chi-square and logistic regression techniques.

RESULTS: No significant differences were observed between UP and BP homeless demographics. The bipolar depressed homeless (BDH) group displayed a higher percentage of Central Nervous System (CNS) Stimulants (χ 8.66, p=0.004) and Opiates (χ 6.41, p=0.013) as compared to the unipolar depressed homeless (UDH) group. CSN Stimulant was the only predictor within the BDH Group (χ(2) 8.74 df 1 p<0.003).

LIMITATIONS: Data collected are self-reported and no urinalyses were performed.

CONCLUSIONS: The results support the hypothesis that beyond the self-medication hypothesis, bipolarity is strictly correlated to substance use; this correlation is also verified in a homeless population.