The contribution of childhood maltreatment to the incidence of heavy cannabis use in Iran (IRNS-CCI): A multicenter, matched-pairs, nested, case-control study.

BACKGROUND: Previous studies have shown the role of the interaction between the endocannabinoid system (ECS) and life's adversities in the formation of addiction, including alcohol abuse.

OBJECTIVE: Our objective was to identify childhood maltreatment (CM) patterns with the strongest impact on the probability of heavy cannabis use (THCCOOH concentrations ≥150 ng/mL) in Iran.

PARTICIPANTS AND SETTING: Using survivor sampling, 350 adult participants were selected, and they were then allocated to three categories based on an optimal algorithm: 1) Sexual abuse, 2) Physical abuse, and 3) Physical neglect.

METHODS: From 1 September 2019 to 1 May 2023, we implemented a multicenter, matched-pairs, nested, case-control study based on the wave 3-wave 6 data of a longitudinal, multicenter, cohort study. The cases and controls (n = 350 men) were defined according to the severity of CM. The THC potency was evaluated with the delta-9 carboxy tetrahydrocannabinol (THC-COOH) levels in urine using gas chromatography/mass spectrometry (GC/MS). We calculated the population attributable fractions (PAFs) to identify the patterns of maltreatment associated with the highest odds of high-potency cannabis use.

RESULTS: Accumulating CM, including sexual abuse, physical abuse, and physical neglect, carried more than three times the risk of heavy cannabis use (OR 3.4 95 % CI 2.9-4.1), and the combination of the three indicators of maltreatment and a high BMI (25-29.9) carried more than four times the risk of heavy cannabis use (OR 4.7 95 % CI 2.7-4.1) compared to the controls. We estimated that in the case of zero CM for each of the three indicators, over 20 % of new cases of heavy cannabis use can be prevented.

CONCLUSIONS: The findings show the significance of CM as a predicator of heavy cannabis use in adulthood and in the abstinence phase.