Anxiety and Depression As Predictors of Long Term Abstinence Among Stimulant Dependent Outpatients in a Clinical Trial of Concurrent Smoking Cessation and Substance Abuse Treatment

Purpose: The purpose of the current study was to examine the presence of anxiety and depression and associated substance use treatment outcomes among a sample of stimulant dependent patients from a multi-site randomized control trial evaluating the impact of concurrent smoking cessation treatment (SCT) and community based outpatient stimulant treatment. Additionally, the study sought to examine the impact of antidepressant medication, used as part of SCT, on depressive symptoms and substance abuse treatment outcomes.

Methods: Participants (N=538) were recruited from 12 community-based substance abuse treatment programs, met DSM-IV-TR diagnostic criteria for current cocaine or methamphetamine dependence, and were enrolled in treatment for stimulant use disorder treatment. Participants were randomly assigned to treatment as usual (TAU) or to treatment as usual with smoking-cessation treatment (TAU+SCT) as part of a 10-week, intent-to-treat, 2 group, Smoking Cessation and Stimulant Treatment (S-CAST, CTN-0046) conducted within the NIDA Clinical Trials Network (CTN). TAU+SCT received smoking cessation treatment (SCT) which included extended-release (XL) bupropion. Mood outcome was evaluated using the Hospital Anxiety and Depression Scale (HADS).

Results: Participants (N=538) reported experiencing at least some anxiety (n=212, 39.4%) or depression (n=81, 15.1%) at baseline, the majority of those were categorized as mild or moderate (for anxiety, n=184, 34.2%, and for depression, n=80, 14.9%). Scores at baseline (anxiety scores M=6.7, SD=4.2; depression scores M=4.0, SD=3.4) significantly decreased (t=17.81, df=476, p<.001 for anxiety; t=12.99, df=476, p<.001 for depression) by week 10 (anxiety scores M=3.2, SD=3.7; depression scores M=2.0, SD=3.0). No significant differences were observed between the TAU and TAU+SCT groups either at baseline or at week 10 immediately following conclusion of treatment. These significant improvements during the course of treatment represented an approximately 50% reduction in reported depression and anxiety. Depression and anxiety were found to significantly predict SUD treatment outcomes with increased self-reported symptom severity predicting greater substance use at the conclusion of treatment (week 10) and the follow-up points of three and six months. Specifically, for every point increase in their anxiety scores at baseline, participants were approximately 7-8% less likely to remain abstinent from stimulants, and for every point increase in their depression scores at baseline, participants were 10-13% less likely to remain abstinent at week 10, three month, and six month follow-up.

Implications: The results emphasize the prevalence of depression and anxiety among patients with stimulant dependence, and their impact on substance abuse treatment outcomes. In spite of treatment with antidepressant medication for those in SCT, significant improvement in mood occurred for all participants during active treatment, with no difference between groups. This study highlights the need for attention to comorbid psychiatric disorders during substance use treatment to sustain improvements made in mood and to achieve long term abstinence, especially for people with depression and anxiety disorders, who are at particularly greater risk for relapse.