Comparative study of the perceived quality of life of patients in treatment for cocaine and heroin dependence in Spain: differences by gender and time in treatment.

This is a cross-sectional study in which we compared the perceived quality of life (QoL) of patients receiving outpatient treatment for cocaine (n = 727) and heroin dependence (n = 469), by analyzing differences by gender and time in treatment. Participants were recruited from addictive behavior centers in Spain in 2004. The World Health Organization Quality of Life Assessment Instrument (WHOQOL-Bref) was used as a measure. Analysis of covariance and multivariate linear regression were used. This study shows the relevance of considering the role of gender in QoL studies, and the need to evaluate the effectiveness of treatment in the improvement of QoL. Limitations of the study were noted.