Replicating the Dimensional Structure of Cannabis Problems: A Taxometric Analysis

This study employed taxometric procedures to replicate a previous report of the dimensional structure of problems related to cannabis consumption. Method: Over 4,000 cannabis users completed an assessment of psychological, social, occupational, and physical harms (the Marijuana Problems Scale). Three taxometric procedures (MAMBAC, MAXEIG, and L-Mode) compared the current data to simulations with a base rate of problematic cannabis use derived from representative, large-scale data estimates. Results: All three procedures confirmed the continuous, dimensional nature of these cannabis problems and suggested no underlying taxon or category. Conclusions: Psychopathological disorders, including some substance use problems, have fit categorical models suggesting that they differ in kind (rather than intensity) from the behavior of the rest of the population. Cannabis problems, however, appeared to lie along a continuum with other forms of use. Given heightened awareness for the necessity of replication and a changing legal landscape for cannabis, a second look at the dimensionality of these problems seemed warranted. New data with a larger sample and different indices of problematic use confirmed the dimensionality of cannabis problems. This replication can inform predictions about the etiology, prevention, and treatment of cannabis use disorder. Researchers should expect cannabis problems to range along a continuum without categorical distinctions. Dividing users into groups of problematic and non-problematic users likely sacrifices meaningful variance. Harm reduction strategies likely can benefit all users rather than a targeted taxon with troubles. In addition, interventions will likely progress by small, incremental steps rather than dramatic, categorical jumps in progress.