Text-Message Cannabis Treatment Worked Indirectly by Boosting Motivation and Harm Reduction Skills

No significant direct treatment effects on cannabis use were found between PNC-txt and control. However, PNC-txt significantly increased readiness to change and protective behavioral strategies at 1 month, which mediated decreases in cannabis use days from baseline to 6 months. The treatment works through its hypothesized clinical mechanisms rather than through direct behavioral change.

RCT with 1,078 US young adults from Colorado and Tennessee randomized to 4-week PNC-txt or wait-list control, followed 6 months. Latent change score mediation modeling tested indirect effects through readiness to change and protective behavioral strategies.

Understanding how treatments work is as important as knowing whether they work. This companion paper to the mediation analysis reveals that the text-message approach succeeds by activating motivation and teaching harm reduction, not by directly changing behavior. This has implications for refining and improving the intervention.

Many addiction treatments show indirect rather than direct effects, meaning they change the psychological precursors to behavior change rather than behavior itself. This is consistent with motivational interviewing theory and validates the text-message delivery format for activating these mechanisms.

Wait-list control design. Mediation analysis is observational even within an RCT. The indirect-only effect pattern means the treatment may not help people who are not responsive to motivational approaches. Colorado and Tennessee represent different cannabis policy contexts.