Impact of substance dependence and dual diagnosis on the quality of life of heroin users seeking treatment.

In 189 opioid-dependent subjects on methadone maintenance treatment in Barcelona (Spain), we assessed the prevalence of co-occurrence substance use and non-substance-use disorders (dual diagnosis) by the Psychiatric Research Interview for Substance and Mental Disorders [PRISM], and the impact on quality of life (HRQoL) by the SF-12 (PCS-12 and MCS-12 scales). Rates of substance and non-substance-use diagnoses were 59% and 32%, respectively. Mean scores for PCS-12 and MCS-12 were 44.1+/-10.1 and 39.9+/-11.7, without differences by presence or absence of dual diagnosis. Heroin users on methadone treatment showed a high prevalence of dual diagnosis and a very impaired HRQoL.