Long-term functioning to provide empirical support for the clinical relevance of treatment outcomes for...

Research has yet to empirically evaluate methamphetamine (MA) use outcome measures commonly used to indicate treatment success. Clinically meaningful outcomes must be associated with long-term functioning in important life domains. This study evaluated the association between different MA use outcomes and long-term life-functioning.

The data that this study used in its secondary analyses were pooled from two treatment trials for MA use disorders (n = 237). The study conducted multiple regression analyses (with multiple imputation for missing data) to determine the association of six within-treatment MA use outcome measures with problem severity in seven life domains and a proxy measure for overall functioning, measured with the Addiction Severity Index (ASI) and assessed at an 8-month follow-up.

The longest duration of abstinence (LDA) outcome achieved the most consistent performance, being associated with better scores in five of eight ASI outcomes (β ranging from -0.203 to -0.291; p < .01). The complete abstinence during treatment demonstrated the poorest performance and was not significantly associated with any of the ASI outcomes. All other MA use outcome measures were significantly (p < .01) associated with at least one ASI outcome.

This study provides empirical support for the use of LDA as a clinically relevant indicator of treatment success for MA use disorders, while also indicating the limitations of using complete abstinence during treatment to determine treatment success. Based on these findings, providers and researchers should use LDA as a primary outcome for MA use disorder treatments and trials.