Beyond frequency of use: Exploring additional metrics for quantifying cocaine use and their relation to life functioning and treatment outcome.

Background: Frequency of use - the number of days of use - is the most common metric for quantifying cocaine use and the most common target of treatment. However, frequency may not capture all important aspects of cocaine use. This study examined how other aspects of cocaine use (typical amount spent, variability etc.) relate to life functioning and cocaine use disorder (CUD) treatment outcomes.

Method: This is a secondary analysis of 3 clinical trials for CUD, N = 207 for the life functioning analysis and N = 173 for the outcomes analysis. Eight metrics of use were calculated from baseline 30-Day Timeline Followback (TLFB) data and entered into multiple regression and hierarchical Poisson regression analyses predicting domains of the Addiction Severity Index and treatment outcomes, respectively.

Results: Greater typical dollar amount used (i.e., generally greater amounts of cocaine used per occasion) related to better employment functioning, while better treatment outcomes were associated with: 1) less frequent use, 2) greater typical dollar amount used, 3) more variability in dollar amount, 4) less weekday use, 5) greater variability in days between uses, and 6) a downwards trajectory in frequency of use and upwards trajectory in typical dollar amount over the month leading into treatment.

Conclusions: Beyond days of use, other aspects of use also relate to life functioning and treatment outcomes, although these aspects predicted treatment outcomes better than life functioning. Future work should explore whether other aspects of cocaine use are important targets for harm-reduction-focused treatment.