Characterizing cannabis use reduction and change in functioning during treatment: Initial steps on the path to new clinical endpoints

Abstract

Reduction-based cannabis use endpoints are needed to better evaluate treatments for cannabis use disorder (CUD). This exploratory, secondary analysis aimed to characterize cannabis frequency and quantity reduction patterns and corresponding changes in psychosocial functioning during treatment. We analyzed 16 weeks (4 prerandomization, 12 postrandomization) of data (n = 302) from both arms of a randomized clinical trial assessing pharmacotherapy for CUD. Cannabis consumption pattern classes were extracted with latent profile modeling using self-reported (a) past-week days used (i.e., frequency) and (b) past-week average grams used per using day (i.e., quantity). Changes in mean Marijuana Problem Scale (MPS) and Hospital Anxiety and Depression Scale (HADS) scores were examined among classes. Urine cannabinoid levels were examined in relation to self-reported consumption as a validity check. Two-, three-, four-, and five-class solutions each provided potentially useful conceptualizations of associations between frequency and quantity. Regardless of solution, reductions in MPS scores varied in magnitude across classes and closely tracked class-specific reductions in consumption (e.g., larger MPS reduction corresponded to larger frequency/quantity reductions). Changes in HADS scores were less pronounced and less consistent with consumption patterns. Urine cannabinoid levels closely matched class-specific self-reported consumption frequency. Findings illustrate that frequency and quantity can be used in tandem within mixture model frameworks to summarize heterogeneous cannabis use reduction patterns that may correspond to improved psychosocial functioning. Going forward, similar analytic strategies applied to alternative metrics of cannabis consumption may facilitate construction of useful reduction-based clinical endpoints. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Trial registration: ClinicalTrials.gov NCT01675661.

Figure 1.

Different latent class solutions using self-reported cannabis frequency (days) and quantity (grams) during each study week

Figure 2.

Psychosocial outcome scores over time across classes and class solutions *Week −1 = week prior to randomization; Models adjusted for Treatment Status, Age, Race, Gender; Estimates are adjusted predictions at means of covariates

Figure 3.

Self-reported days used vs. urine cannabinoid levels over time across different latent class solutions