HIV, the brain, and behavior, and most importantly, about their interactive nature. Chief interactions discussed in Chapter 4 include: (1) HIV infection of the brain and the effects it has on the central nervous system; (2) effects of interactions among HIV infection, substance use, and mental illness, and the unique medical care and treatment issues associated with such interactions; and (3) the relationship between psychosocial factors and HIV infection for individuals with the disease, as well as for their loved ones and caregivers.
HIV-associated conditions affecting both the central nervous system (CNS) and the peripheral nervous system (PNS) are common and result in considerable morbidity and mortality. Some conditions are secondary complications of HIV infection, resulting from opportunistic infections or systemic organ dysfunction that follows from immune deficiency induced by HIV infection. Among these are cerebral toxoplasmosis, primary CNS lymphoma, cryptococcal meningitis, and progressive multifocal leuko-encephalopathy.
Other conditions likely result directly from HIV infection itself. The pathogenesis of these primary complications is not yet clearly understood, but they are thought to be sequelae of interactions among HIV, the immune system, and various components of the nervous system. These conditions include, at the early stage of HIV infection, mild meningitis with headache. As the infection progresses, patients may experience "aseptic" meningitis, peripheral neuropathy, and, most significantly, a set of afflictions collectively known as AIDS dementia complex (ADC).
In its mild form, ADC syndrome slows intellectual processing, blunts concentration and impairs rapid and fine motor control. When more severe, it can dull the personality and cause truly devastating dementia that reduces the patient to a shell of his or her former self, impairs walking, and, eventually, leaves the victim bedridden, incontinent, and mute (Navia et al., 1986; Navia, Jordan, and Price, 1986; Price and Sidtis, 1992). ADC can be a source of protracted and severe disability, modifying and markedly diminishing the quality of remaining life, reducing enjoyment of work and daily life, depriving the patient of social and intellectual pleasures, and requiring emotionally and financially costly care.
The core features of the ADC have now been well characterized,