Previous research on the relationship between cannabis and posttraumatic stress disorder (PTSD) has produced equivocal results. One explanation is that differences in cannabis use characteristics (e.g., medicinal vs. recreational use, route of administration, THC to CBD ratio, and grams per day) are associated with differences in PTSD severity. Using data from a previous cross-sectional study, we performed a series of MANOVAs to examine how cannabis use, cannabis use characteristics, sex, and talk therapy attendance are associated with PTSD severity, psychological distress (i.e., depression and anxiety), and insomnia in a sample of Canadian veterans with chronic pain and a history of trauma (N = 513). We also performed descriptive analysis on participants’ demographics, military history, and cannabis use. Participants with a cannabis prescription and/or who attended talk therapy tended to have higher PTSD severity than those who did not. Cannabis use, sex, route of administration, THC to CBD ratio, and grams per day, were not significantly correlated with PTSD-related outcomes. However, descriptive analysis showed that the majority of those who used cannabis reported that it benefited their mental health. We speculate that veterans with more severe PTSD are more likely to seek out treatment in the form of prescribed cannabis or talk therapy; and that the perceived effect of cannabis on PTSD differs from the measured effect due to cannabis only causing a short-term reduction in PTSD symptoms.