Longitudinal association between frequency of substance use and quality of life among adolescents receiving a brief outpatient intervention.

Recognition of the broad consequences of adolescent substance abuse has led to increased emphasis on balancing traditional measures of treatment effectiveness, such as frequency of substance use, with measures of patient functioning and quality of life (QOL). This study evaluated the longitudinal association between frequency of use and QOL among adolescent substance abusers receiving a brief outpatient intervention. Participants were 106 adolescents, aged 13 to 21 years, who met criteria for substance abuse or dependence and completed 4 assessments over a 12 month period. Results of a parallel-process latent growth curve model indicated a moderate longitudinal association, such that reduced frequency of use was associated with QOL improvement. Elaboration of the temporal ordering of this association via a cross-lagged panel model revealed that frequency of substance use predicted subsequent QOL, but that QOL did not predict subsequent frequency of use. Implications pertaining to the assessment of comprehensive outcomes and the setting of treatment expectations are discussed. 2009 APA, all rights reserved.