Background: Research shows that many people exhibit comorbid psychiatric disorders and initiation of drug use and can interact negatively on each other. Overall, psychiatric comorbidity has a great impact on the clinical severity, psychosocial functioning of patients with substance use disorders. Because people may may self-medicate psychiatric disorders through drug use and subclinical symptoms may also prompt drug use. Also drug use may increase vulnerability to psychiatric disorders by exerting neurophysiological or behavioral changes on the user . the aim of this study was to determine psychiatric disorders associated with the onset of drug use. Methods: Study method was cross- sectional. Research statistics universe constitutes of all People suffering substance dependence disorder in Tehran and Hamedan city. The sample consisted of 235 individual with substance dependence disorder, that selected from harm reduction centers in Tehran and Hamedan city, The sampling selection method was simple random. We used the SCL90-R questionnaire to evaluate psychological disorders associated with initiation of drug use. Results: results showed that mental disorders were associated with the initiation of drug use. psychological disorders affecting the initiation of drug use, respectively, sadness, depression, anxiety, aggression, sexual dysfunction. Conclusions: The study findings suggest an urgent need to expand and improve diagnostic and treatment capabilities and Select an integrated approach, where both the substance abuse problem and the mental disorder are treated simultaneously.
