A relational agent for treating substance use in adults: A randomized controlled trial with a psychoeducational comparator.

BACKGROUND

Highly accessible and scalable, digital mental health interventions can reduce barriers associated with traditional treatment. Woebot for Substance Use Disorders (W-SUD) is a smartphone application in development that uses Woebot, a guided self-help relational agent intended to offer support to track and reduce problematic substance use. Two formative studies supported W-SUD's feasibility, acceptability, and efficacy to reduce substance use at end-of-treatment (EOT).

OBJECTIVES

In a randomized trial with a 1-month post-treatment follow-up, we aimed to evaluate W-SUD's efficacy in reducing substance use occasions relative to a psychoeducational control.

METHODS

U.S. adults (N = 258) with problematic substance use (CAGE-AID≥2) were recruited online and randomized to W-SUD or an email-delivered psychoeducational control. Primary and secondary outcomes were change in past-month substance use occasions from baseline to 8-weeks EOT and baseline to 1-month follow-up, respectively.

RESULTS

The analytic sample (N = 202; 107 = W-SUD; 95 = psychoeducation) averaged 38.3 years of age (SD = 10.4) and was 53.5% (108/202) female and 71.3% (144/202) White. At baseline, participants averaged 33.1 (SD = 18.3) past-month substance use occasions with problematic substance use reported as alcohol (73.3%, 148/202), cannabis (30.7%, 62/202), stimulants (17.3%, 35/202), and cocaine (12.4%, 25/202). Anxiety (32.7%, 66/202) or depression (23.3%, 47/202) co-occurred. W-SUD participants sent a median of 322.5 (interquartile range: 59.8, 924.0) in-app messages during the intervention. There was no significant treatment effect on the primary (beta = -0.675, p = 0.741; 95%CI = -4.96-3.49) or secondary outcomes. Baseline to EOT within-group change in past-month substance use occasions were -13.6 (SD = 15.4, d = -0.879) and -12.9 (SD = 15.3, d = -0.847) for the W-SUD and psychoeducation conditions, respectively, indicating moderate to large changes in both, which was sustained at 1-month follow-up. Decreases in substance use occasions significantly correlated with decreases in anxiety and depression and with greater treatment satisfaction in both groups. There were no serious adverse events.

CONCLUSIONS

Participants in both conditions reported significant improvements in primary and secondary outcomes at EOT and 1-month post-treatment, with no statistically significant difference in improvement between conditions.

CLINICALTRIALS: GOV (POSTED 2021-06-14): NCT04925570, https://clinicaltrials.gov/study/NCT04925570.