Anxiety, mood disorders and injection risk behaviors among cocaine users: Results from the COSMO study.

Background And Objectives: Despite being common among cocaine users, mental health problems and their relationship with HIV and hepatitis C high risk injection behaviors are poorly documented. This study was undertaken to examine the relationships between mood and anxiety disorders and the sharing of drug injection equipment among cocaine users who inject drugs.

Methods: The sample was drawn from a prospective cohort study and comprised of 387 participants. The outcome of interest was "sharing injection material" in the past 3 months. The presence of mood and anxiety disorders during the past year was assessed using the CIDI questionnaire. Statistical analyses were conducted on baseline data using logistic regression.

Results: Most participants were male (84.5%) and were aged 25 or over (92.2%); 43.0% qualified for an anxiety disorder diagnosis and 29.3% for a mood disorder diagnosis. Participants with anxiety disorders were more likely to share needles (Adjusted Odds Ratio [AOR]: 2.13, 95%CI: 1.15-3.96) and other injection material (AOR: 1.81, 95%CI: 1.12-2.92). No significant association was found between mood disorders and sharing behaviors.

Discussion And Conclusions: Primary anxiety disorders but not mood disorders increases injection risk behaviors among cocaine users. These results bring to light another negative outcome of mental health comorbidity in this vulnerable population.

Scientific Significance: This study underlines the need to fine-tune therapeutic approaches targeting specific mental health problems in individuals with cocaine use disorders. Longitudinal studies that assess impulsivity and other correlates of psychiatric disorders are needed to examine underlying mechanisms of high risk injection behaviors in comorbid populations.