Short and long-term improvements in psychiatric symptomatology to validate clinically meaningful treatment outcomes for cocaine use disorders

Background: Substantial efforts have been made to identify clinically meaningful non-abstinence cocaine use outcomes by establishing associations between targeted drug use outcomes and long-term functional improvements. Psychiatric symptomatology is prevalent among those seeking treatment for cocaine use disorder (CUD). Establishing an association between cocaine use outcomes and improvements in psychiatric symptomatology would support clinical validity to these outcome measures.

Method: With data pooled from 5 clinical trials evaluating treatment for CUD (n = 474) multiple linear mixed models were conducted to determine how five specific cocaine use outcome measures performed in terms of improvements in psychiatric symptomatology assessed with the Brief Symptom Inventory (BSI) at baseline, end-of-treatment and 6-month follow-up.

Results: Three outcome measures performed comparably well (maximum days of consecutive abstinence, 3 or more weeks of abstinence and end-of-treatment abstinence), in that they consistently predicted improvements in several BSI composite scores at the end-of-treatment and follow-up. The poorer-performing outcome measures were complete abstinence during treatment, percentage of negative urinalysis results and percentage of days abstinent. Improvements in the BSI's global index of distress, positive symptom total, as well as depression, interpersonal sensitivity, obsessive-compulsion, phobic-anxiety and psychoticism dimensions were consistently associated with outcome effects, while anxiety, hostility, paranoid ideation and somatization were not.

Conclusion: The consistent short and long-term association of three outcome measures evaluated here (maximum days of consecutive abstinence, 3 or more weeks of abstinence and end-of-treatment abstinence) with improvements psychiatric symptomatology adds support to their clinical relevance as well as their adoption in trials and treatments for CUD.