Participants were male and female alcohol, opiate, cocaine, and methamphetamine users enrolled in an outpatient treament progra-m at any of 8 sites.

• 参与者为登记在8处门诊病人治疗计划任何一处之男性和女性的酒精、类鸦片、古柯碱和甲基安非他命使用者。