There are several limitations to this report that warrant discussion. First is the sample size and associated modest statistical power, especially for the detection of sex effects (Prescott & Gottesman, 1993). It is possible that we did not have the power to detect these differences. Second are the limitations with the substance use measure. Most notably is that the questions asked were not consistent across waves so we were forced to create comparable categories. A self-report questionnaire was also used that was mailed to the participant’s home. However, participants may be more likely to reveal private information in this manner.
