For over two decades, the world has witnessed a devastating epidemic brought on by the HIV. In combating this epidemic, many researchers have grappled with the psychological and social facets of disease proliferation. Particularly over the past decade, infection with HIV has been found to be associated with risky behaviors, such as unprotected sex, promiscuity, and intravenous drug use (Holmberg, 1996
). Furthermore, it has been suggested that risk may be a function of decision-making style. Thus, deci sion-making style is an important area of study both in individuals at risk for HIV infection and in those who are already HIV positive (HIV+). Such knowledge could allow for the development of countermeasures, such as prevention and education programs that target at-risk individuals. For those who are already infected, decisions made take on the greatest salience in areas such as medication adherence, abstinence from substances that might compromise their immune systems, and further unprotected sexual contact.
Assessing the degree and type of risky behaviors in persons at risk for or infected with HIV is important. Also relevant is the investigation of the cognitive mechanisms underlying these decisions. Neurocognitive instruments are commonly employed to investigate the cognitive operations underlying observed behavior. One such instrument, referred to as the gambling task (Bechara, Damasio, Damasio, & Anderson, 1994
), was developed in order to investigate the decision-making strategies in individuals with frontal lobe lesions. The task includes four decks of cards from which to choose, with each selected card resulting in either winning or losing a sum of replica money. The arrangement of the decks is such that selection from two of them will result in a net profit by the end of the task, while card selection from the other two will result in a loss. The decks that result in the net loss, however, offer larger payoffs than the others early on. Through its design, this task assesses participants’ capacity for prudent decision making and risk taking by tracking which decks they draw from, thereby measuring their responses to reward/punishment and concern for future outcomes. A number of studies have found that bilateral lesions of the ventromedial prefrontal lobe (VM) are associated with poor (i.e., risky) performance (Bechara, Damasio, Damasio, & Lee, 1999
; Bechara, Damasio, Tranel, & Anderson, 1998
; Bechara, Tranel, & Damasio, 2000
), while left-sided lesions do not affect performance (Manes et al., 2002
). From these studies, it appears that such lesions result in a decision-making that is based on immediate gratification with little concern for future outcome.
Research into the decision-making characteristics of substance abusers (Grant, Contoreggi, & London, 2000
), including HIV-infected substance abusers (Martin et al., 2004
), has also employed the gambling task. Substance abusers and VM individuals often overlap in real-life behaviors in which they opt for choices that result in immediate reward despite the potential for negative consequences, and this observation has been replicated with the gambling task (Bechara et al., 2001
; Bechara, Dolan, & Hindes, 2002
; Bechara & Damasio, 2002
). The gambling task has also been used in studies of individuals with neurodegenerative disease. Stout, Rodawalt, and Siemers (2001)
examined decision making in individuals with Huntington’s disease (HD) or Parkinson’s disease (PD) as compared to that of healthy controls. HD primarily affects the basal ganglia. Thus, the authors hypothesized that because of the high connectivity between the basal ganglia and prefrontal cortex, behaviors such as poor decision making seen in those with frontal lobe lesion would also be seen in the HD group. As expected, they found that the HD group demonstrated increased risky decision-making compared to the controls and PD group, such that the HD group drew more from disadvantageous decks even when they appeared to know such decks were “bad.”
HIV infection can also lead to neurocognitive degeneration, leading to a range of symptoms from subtle subclinical cognitive decline to outright dementia (Hinkin, Castellon, van Gorp, & Satz, 1998
). Frontostriatal circuits and subcortical nuclei to which they connect are most commonly affected by HIV neuropathological change, and there is appreciable overlap in those areas affected by HD and HIV. Therefore, it is reasonable to expect similar neurocognitive and behavioral changes to occur in HIV.
In the current study, we describe the performance of HIV+ individuals on the gambling task compared to that of HIV− controls. It is expected that the HIV+ group will exhibit greater decision-making deficits, based on both the psychosocial and neurocognitive factors described above. A novel component to our study, relative to previous gambling task studies, is that we examine performance separately for each card deck to further characterize HIV-related decision making. The rationale for this further analysis is that contingencies differ across decks. For instance, although the disadvantageous decks produce the same immediate reward and average losses, one deck includes frequent but smaller penalties while the other includes infrequent but larger penalties. The cognitive mechanisms involved with such decision making may be susceptible to such differences in reward/punishment contingencies. Related to this point, we have also considered the potential role of neurocognitive processes on gambling task performance, and provide measures of attention and executive abilities as well as other test measures (psychomotor and processing speed, concept development, and verbal memory) in assessing neurocognitive differences between HIV+ and HIV− participants and the potential mediating role of such processes in gambling task performance. Many previous studies failed to find appreciable correlations between neurocognitive measures sensitive to frontal lobe dysfunction and the gambling task (e.g., Bechara et al., 1998
; Grant et al., 2000
). This may be the case in HIV-infected adults as well, although we have no strong predictions about this.