infection. It found that SMI-HIV patients had high rates of risky behavior, including sex with a known injection drug user, prostitution, and male–male sexual contact (Meyer et al., 1995).

There is a paucity of research on the impact of MI on risk of injection drug use. While comorbidity of MI and a substance use disorder is common, and lifetime rates of injection drug use are quite high among those with SMI, there is little information on whether injection drug practices are related to HIV transmission. For example, it is unknown whether persons with MI who engage in injection drug use participate in needle exchange programs or use bleach to clean needles (Sullivan et al., 1999).

Adherence to Antiretroviral Therapy

The relationship between mental illness and adherence to ARV 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 that depressive symptoms, hopelessness, psychological distress, and overall stress are associated with lower antiretroviral adherence.

Paterson and colleagues (2000) studied 81 HIV patients, with adherence tracked by 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. Relatedly, Singh and colleagues (1999), using the Beck Hopelessness Scale and other measures, found that hopelessness and loss of motivation were associated with non-adherence.

One study of SMI and adherence to ARV conducted by investigators at RAND found that about 40 percent of subjects were adherent (>90 percent adherence), while 31 percent had very poor adherence (<50 percent). The overall average adherence rate was 66 percent of prescribed doses, a rate similar to general clinic or community populations. The fact that a large percentage was adherent defied the conventional wisdom that these individuals 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



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