Comparing substance use and mental health outcomes among sexual minority and heterosexual women in probability and non-probability samples

Objective: To examine similarities and differences in demographics and key substance use and mental health outcomes in a probability sample of heterosexual women and two samples of sexual minority women (SMW), one recruited using probability and the other using non-probability methods. Methods: Using data from four waves of the National Alcohol Survey (NAS; n = 315 SMW; 10,523 heterosexual women) and Wave 3 of the Chicago Health and Life Experiences of Women (CHLEW; n = 688 SMW) study, we examined hazardous drinking, drug use, tobacco use, depression, and help-seeking for alcohol or other drug problems. Results: Compared to SMW in the probability sample, SMW in the non-probability sample were older, more likely to be college educated, and more likely to be in a partnered relationship. Compared to heterosexuals, SMW in both the probability and non-probability samples had greater odds of past-year hazardous drinking, marijuana use, and other drug use. We found similar results for lifetime help-seeking for alcohol or drug problems, past week depression, and co-occurring hazardous drinking and depression. In comparisons with heterosexual women, the magnitude of difference for drug use was greater for the SMW non-probability sample; for tobacco use, the difference was greater for the SMW probability sample. Conclusion: Given the difficulties recruiting probability samples of SMW, researchers will continue to use non probability samples in the foreseeable future. Thus, understanding how findings may differ between probability and non-probability samples is critically important in advancing research on sexual-orientation-related health disparities.