Despite the effectiveness of highly active antiretroviral therapy (HAART) in reducing HIV related morbidity and mortality, not all groups have had equal access to the treatment. Beyond financial and provider-level factors, there is growing evidence that HIV conspiracy theories and distrust in the medical establishment may be acting as a barrier for some populations to receive appropriate care. This study will examine how trust in the medical establishment affects the decision to use, maintain and adhere to HAART therapy among participants in the Women's Interagency HIV Study. Using both longitudinal and cross-sectional data, this study will 1) describe the prevalence of distrustful beliefs among a national cohort of women; 2) identify the characteristics associated with more distrustful beliefs; 3) determine if distrustful beliefs are associated with decreased use of HAART, more frequent switching of therapy or lack of adherence; 4) describe whether distrustful beliefs have more of an impact among those with substance abuse problems or among members of racial or ethnic minority groups. Identifying factors related to inappropriate use of HAART is critical not only for the health and well-being of seropositive persons, but also for efforts to prevent HIV transmission. ? ? ?