Phenotypic and familial associations between childhood maltreatment and cannabis initiation and problems in young adult European-American and African-American women

- Maltreatment is associated with cannabis initiation before age 15.
- Variance in maltreatment is largely attributable to shared environmental factors.
- Cannabis initiation and problems are genetically influenced.
- Environmental influences on cannabis initiation/problems differ by race/ethnicity.
- Sources of covariation between maltreatment and cannabis differ by race/ethnicity.

BackgroundChildhood maltreatment is a known risk factor for cannabis initiation and problem use, but the extent to which this association is attributable to shared familial influences is unknown. We estimate the magnitude of associations between childhood maltreatment, timing of cannabis initiation, and cannabis-related problems, in European-American (EA) and African-American (AA) women, and parse the relative influence of additive genetic (A), shared environmental (C), and individual-specific environmental (E) factors on these constructs and their covariation.MethodsData were from diagnostic telephone interviews conducted with 3786 participants (14.6% AA) in a population-based study of female twins. Logistic regression analyses and twin modeling were used to test for associations, and estimate the relative contributions of genetic and environmental influences to childhood maltreatment and cannabis outcomes and their covariation.ResultsMaltreatment was significantly associated with increased likelihood of cannabis initiation before age 15 among EAs (OR = 6.33) and AAs (OR = 3.93), but with increased likelihood of later initiation among EAs only (OR = 1.68). Maltreatment was associated with cannabis problems among both groups (EA OR = 2.32; AA OR = 2.03). Among EA women, the covariation between maltreatment and cannabis outcomes was primarily attributable to familial environment (rC = 0.67-0.70); among AAs, only individual-specific environment contributed (rE = 0.37-0.40).ConclusionChildhood maltreatment is a major contributor to early initiation of cannabis as well as progression to cannabis problems in both AA and EA women. Distinctions by race/ethnicity are not in the relative contribution of genetic factors, but rather in the type of environmental influences that contribute to stages of cannabis involvement.