Examining Associations Between Trauma Exposure and Cannabis Use Frequency, Quantity, Duration, and Age of Onset

Prior research has identified an association between trauma exposure and cannabis use, such that a history of trauma exposure is associated with greater likelihood of lifetime cannabis use. However, little research has expanded upon this association, making it unclear whether trauma exposure is associated with cannabis use outcomes beyond lifetime history of use. Given that heavy cannabis use and trauma exposure are risk factors for a number of deleterious outcomes, it is important to further examine the influence of trauma exposure on cannabis use. The purpose of the current study was to further explore this relationship by examining associations between trauma exposure and various indices of cannabis use. Participants included a sample of 722 female undergraduates at least 18 years or older (M = 19.0) who were recruited through a campus-wide online study pool. Participants completed measures on trauma exposure (calculated as number of traumas experienced), cannabis use (i.e., Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use [DFAQ-CU]; Cutler & Spradlin, 2017), and mental health symptoms. Specific indices of cannabis use were lifetime history of cannabis use, age of onset of cannabis use, current frequency of use, current quantity of use (in grams), and length of use. Logistic regression analyses and correlations were used to explore the associations between trauma and cannabis use variables. Subsequent analyses were conducted controlling for posttraumatic stress disorder (PTSD) symptoms to determine whether relationships between trauma exposure and cannabis use remained after accounting for PTSD symptoms. Thirty-seven percent (n = 266) of the sample indicated a lifetime history of cannabis use. Similar to previous research, greater trauma exposure was significantly associated with a greater likelihood of a lifetime history of cannabis use (OR = 1.14, p < .001). Additionally, number of traumas experienced and age of onset of cannabis use were significantly negatively correlated, r(262) = -.16, p < .01, indicating that greater trauma exposure was associated with earlier onset of use. Number of traumas experienced was positively correlated with duration of cannabis use, r(236)=.14, p = .03, indicating greater trauma exposure was associated with greater duration of use. Number of traumas experienced was also positively correlated with quantity of cannabis use, r(175)=.20, p < .01, showing that greater trauma exposure was associated with higher amounts of cannabis used. These associations remained significant even after controlling for PTSD symptoms. Frequency of cannabis use was not significantly correlated with trauma exposure, r(266) = -.01, p = .82. The results of the present study indicate that trauma exposure is associated with a range of indices of cannabis use beyond lifetime history of use, even after accounting for the influence of PTSD. These findings highlight the importance of extending examination of trauma and cannabis beyond frequency of use. Although trauma exposure may serve as a risk factor for elevated cannabis use, it is also possible that cannabis use may increase the risk of trauma exposure. Future studies should explore these associations longitudinally as well as examine the mechanisms that link these outcomes together.