The clusters of symptoms do not reveal the temporal relationship between alcohol and posttraumatic stress symptoms. However, given that the mean age of AUD onset, at 18.7 years, is higher than that of the average age of first trauma exposure for physical assault (15.4 years), sexual assault (12 years), and non-assaultive trauma (13.4 years), we believe it is likely that the majority of the sample experienced some form of trauma at least prior to heavy, sustained alcohol use. Our analysis did not control or account for other types of parental pathology, such as a history of trauma, that might have contributed to offspring risk for problematic alcohol use or PTSD. It is also likely that individuals in our sample may have been experiencing additional symptoms typically associated with another psychiatric disorder (such as depression or conduct disorder) that we did not include among our covariates. As with all measures that ask the participant to self-report past negative experiences, especially trauma, there is the potential of recall bias among our sample. We also did not assess whether the parent with AUD
