the development of heart disease and lower atherosclerosis (Uchino, 2006) and the progression of cardiac disease once diagnosed.
The typical clinical course of HIV infection is a gradual progression from an initial asymptomatic phase, to a symptomatic phase, to the onset of AIDS (CDC, 1992). Individuals differ with respect to the rate at which they progress through these phases. Some remain asymptomatic for extended periods of time and respond well to medical treatment, whereas others progress rapidly to the onset of AIDS, and suffer numerous complications and opportunistic infections (Kopnisky et al., 2004). It has been suggested that psychosocial factors, including stress and depression, may account for some of this variability (Kiecolt-Glaser and Glaser, 1988; Kopnisky et al., 2004; Pereira and Penedo, 2005).
Although the evidence published before 2000 for the influence of stress on progression through the clinical phases of HIV infection was inconsistent (Cohen and Herbert, 1996; Nott and Vedhara, 1999), several studies did report associations between stress due to negative life events and more rapid HIV progression (Goodkin et al., 1992; Kemeny and Dean, 1995; Evans et al., 1997). Studies published since 2000 have been more consistently supportive of such a link (Pereira and Penedo, 2005).7 Evidence also suggests that an accumulation of negative life events over several years of follow-up predicts more rapid progression to AIDS (Leserman et al., 2002). Moreover, stress has been found to influence the course of specific conditions (especially virus-initiated illnesses), to which persons with HIV are especially susceptible (Pereira et al., 2003a,b).
The literature is less clear with regard to the effects of stressful life events on the incidence of cancer. Studies of the effects of stress on the
7One difference between earlier and later studies that may explain the variable findings is that in the most recent studies (started in 1995 or later), some patients have been treated with highly active antiretroviral therapy, a regimen that has substantially reduced AIDS-related deaths among infected persons. Hence the association between stress and HIV progression may be attributable to stress interfering with adherence to this complex medication regimen. Variable findings also may be due to differences in how stress was measured (Cole and Kemeny, 2001). Studies published during the 1990s frequently used aggregate measures of the occurrence of negative life events; later studies tended to incorporate subjective ratings of the stressfulness of events and focus on specific events with highly personal consequences, such as bereavement and the threat of severe illness (Cohen and Janicki-Deverts, 2007).