Several studies suggested a possible link between substance use disorder and attention deficit hyperactivity syndrome (ADHD). The ADHD Rating Scale (ADHD-RS) completed by parents is a tool for diagnosing ADHD in childhood. We adapted this questionnaire for a self-report retrospective scale to estimate the presence of childhood ADHD symptoms in adults. This retrospective questionnaire was completed by 121 heroin dependent patients and 85 age- and sex-matched healthy controls. The ADHD Rating Scale Retrospective Questionnaire is a novel tool for assessing ADHD symptoms that demonstrated high validity. Our results showed strong gender difference in the prevalence of ADHD symptoms, since male subjects obtained higher mean scores of both attention-deficit and hyperactivity scales than females in both the control and the heroin dependent population. Besides, mean score of both scales were higher in the clinical population as a higher portion of substance abusers reported symptoms of childhood ADHD than controls. These results support the hypothesis that untreated childhood ADHD could be a risk factor for developing substance use disorder.