As anticipated, psychiatric or somatic comorbidities were associated with a lower QoL, which is consistent with observations of those patients [4, 9]. Neither the duration of illness nor gender was significantly related to QoL among substance users of our sample according to a cohort of opiate-dependent patients and consistent with findings on patients with anxiety and affective disorders who were administered the Q-LES-Q-SF [4, 28]. Drawing compari- sons with studies previously conducted among substance users is hindered by the fact that they used the Q-LES-Q, which includes eight summary scales that reflect satisfaction with physical health, subjective feelings, work, household duties, school, leisure activities, social rela- tionships, and general activities [29–31].