Recent estimates of mental health morbidity among adults reporting same-gender sexual partners suggest that lesbians, gay men, and bisexual individuals may experience excess risk for some mental disorders as compared with heterosexual individuals. However, sexual orientation has not been measured directly. Using data from a nationally representative survey of 2,917 midlife adults, the authors examined possible sexual orientation-related differences in morbidity, distress, and mental health services use. Results indicate that gay-bisexual men evidenced higher prevalence of depression, panic attacks, and psychological distress than heterosexual men. Lesbian-bisexual women showed greater prevalence of generalized anxiety disorder than heterosexual women. Services use was more frequent among those of minority sexual orientation. Findings support the existence of sexual orientation differences in patterns of morbidity and treatment use.Perspectives on the prevalence of mental health disorders and the need for treatment services among lesbians and gay men have undergone remarkable changes over the last century (Bailey, 1999;Friedman, 1999). Although researchers long ago documented that "illness" models (Gonsiorek, 1996) of homosexuality lacked sufficient empirical support for theoretical predictions (Hooker, 1993), there is increasing concern that lesbians and gay men may be at elevated risk for some psychological disorders because of the harmful effects of social stigma (Fife & Wright, 2000;Kessler, Mickelson, & Williams, 1999;Markowitz, 1998;Meyer, 1995;Otis & Skinner, 1996;Wright, Gronfein, & Owens, 2000). Researchers have shown that some forms of mental disorders, particularly affective, anxiety, and substance use disorders, are likely to be influenced by the effects of social stress (Dohrenwend, 2000;Kendler et al., 1995;Mazure, 1995). In this regard, homosexuality is still widely stigmatized despite greater acceptance evident in recent opinion polls of the American population (Butler, 2001). Lesbians and gay men commonly report positive histories of victimization and discrimination (Herek, Gillis, & Cogan, 1999;Hershberger & D'Augelli, 1995;Krieger & Sidney, 1997), particularly in adolescence or young adulthood (D'Augelli, Hershberger, & Pilkington, 1998;Lock & Steiner, 1999). As a consequence, homosexuality may be a risk indicator for higher rates of psychological distress and some mental disorders.Much of the recent population-based research in this area (Bloomfield, 1993;Cochran, Keenan, Schober, & Mays, 2000;Cochran & Mays, 2000a, 2000bFaulkner & Cranston, 1998;Fergusson, Horwood, & Beautrais, 1999;Garofalo, Wolf, Wissow, Woods, & Goodman, 1999;Gilman et al., 2001;Herrell et al., 1999;Lock & Steiner, 1999;Remafedi, French, Story, Resnick, & Blum, 1998;Saewyc, Bearinger, Heinz, Blum, & Resnick, 1998;Sandfort, de Graaf, Bijl, & Schnabel, 2001;Stall & Wiley, 1988) was made possible by the serendipitous inclusion of questions concerning genders of sexual partners in large healthrelated studies of the gen...