mental illness and HIV were more likely to experience barriers to care than those with HIV alone (Personal communication, A. Fremont, RAND Corporation, 2002). Barriers to care were measured by a 3-item index—not getting needed medical care, going without care because of lack of money, or going without food in order to pay for care.

The relationship between mental illness and adherence to HAART has been investigated in several studies, most of which relied on measures of depression or anxiety symptoms or distress rather than psychiatric diagnoses per se. Although not all studies have found a relationship between adherence and psychological well-being, a number of studies have found depressive symptoms, hopelessness, psychological distress, and overall stress to be associated with lower antiretroviral adherence.

Paterson and colleagues (2000) studied 81 HIV patients, and tracked adherence with a microelectronic monitoring system. The study found that active psychiatric illness, primarily depression, was an independent risk factor for nonadherence, and that nonadherence was significantly associated with treatment failure. Catz and colleagues (2000) also found that depression was a risk factor for self-reported nonadherence in a sample of 72 patients at a teaching hospital. A study in Spain by Gordillo and colleagues (1999) of 366 patients also found that depression was a risk factor for poor adherence. Chesney and colleagues (2000), studying 75 patients at 10 United States sites, determined that nonadherent patients reported higher levels of perceived stress. Singh and colleagues (1999), using the Beck Hopelessness Scale and other measures, found that hopelessness and loss of motivation were associated with nonadherence.

One study of serious mental illness and adherence to HAART conducted by investigators at RAND found that about 40 percent of subjects were adherent (more than 90 percent adherence), while 31 percent had very poor adherence (less than 50 percent) (Personal communication, D. Kanouse, RAND Corporation, 2002). The 47 participants in this study had bipolar depression (n=24), schizophrenia (n=12), schizoaffective disorder (n=5), or psychotic depression (n=6). The overall average adherence rate was 66 percent of prescribed doses, a rate similar to general clinic or community populations. The finding that a large percentage of participants were adherent to their drug defied conventional wisdom that individuals with serious mental illness lack the capacity to adhere to a complex dosing schedule. Still, a third of the sample had very poor adherence, a finding that prompted the investigators to suggest further research to identify barriers and inform the development of tailored interventions for those with serious mental illness to achieve greater adherence, and thus greater treatment benefits.

In summary, the research on mental illness and adherence to HAART indicates that symptoms of depression and psychological distress are associ-



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