In sum, research from epidemiological studies has indicated that sexual minorities have increased prevalence of mental disorders (Meyer, 2003) and comorbid psychiatric conditions (Cochran et al., 2003; Fergusson et al., 2005), as well as earlier disorder onset and greater persistence (Gilman et al., 2001), at least among a subset of disorders. Despite the methodological improvements of these epidemiological studies over previous research, the small sample sizes of sexual minorities (typically under 100 participants) have reduced the ability to detect significant effects (e.g., persistence; Gilman et al., 2001) and to examine potentially important sub-group differences (e.g., sex; Fergusson et al., 1999). In addition, studies have used different operationalizations of sexual orientation (e.g., self-identification, sexual behavior), which can affect the observed relationships between same-sex sexual orientation and health outcomes (McCabe, Hughes, Bostwick, & Boyd, 2005; Midanik, Drabble, Trocki, & Sell, 2007). Future research with larger samples of sexual minorities is needed to address these issues. The addition of questions assessing multiple dimensions of sexual orientation, including self-identification, sexual behavior, and attraction, to recent large-scale epidemiological surveys (e.g., Youth Risk Behavior Surveillance Study
