Cannabis use regimens in trauma-exposed individuals: Associations with cannabis use quantity and frequency

•PRN and PRN+ cannabis use regimens made up most regimens used by trauma-exposed cannabis users (52.1 % and 39.4 %, respectively), while RS regimens only made up 8.5 %.•100 % (9/9) of individuals who began as RS users moved on to a regimen that included PRN use (PRN or PRN+).•The largest proportion of the sample began and remained as PRN users (40.2 % of the total sample or 52.7 % of those who were originally PRN users (37/70)).•Those using cannabis with both PRN-only and PRN+ regimens used cannabis significantly more often per month than those using with RS regimens.•No significant differences were found between any of the regimens by dose per occasion. People with trauma histories have an increased odds of cannabis use. Little is known about the frequency or consequences of different cannabis use regimens in cannabis users with trauma histories. Individuals with anxiety disorders tend to administer benzodiazepines in a pro re nata (PRN; i.e., as needed) as opposed to regularly scheduled (RS, e.g., twice daily [BID], three times daily [TID]) manner. Although physicians tend to prescribe benzodiazepines on a PRN regimen to minimize use, this regimen is paradoxically associated with greater use levels. Indeed, PRN administration regimens may increase use via negative reinforcement processes. We extended this older benzodiazepine literature to cannabis by examining regimen of cannabis use among 94 trauma-exposed cannabis users (mean age = 35.1 years; 52.1 % male; 23.4 % with cannabis prescription). Participants reported their initial and current cannabis use regimen (PRN vs. RS vs. both [‘PRN+’]) and their past month cannabis use frequency (use occasions in last month) and quantity (grams/use occasion). Consistent with patterns in benzodiazepine research, PRN (47.1 % of sample) and PRN+ (43.5 % of sample) were more common than RS regimens (9.4 % of sample). Also consistent with patterns seen with benzodiazepines, our sample moved toward PRN regimens from initial to current use: e.g., 100 % of initial RS users switched to a regimen that included PRN use. Consistent with predictions emerging from learning theory, PRN and PRN+ cannabis users reported significantly higher cannabis use frequencies compared to RS users (p’s