Psychiatric Aspects of HIV Infection and AIDS

Overview

Once a dread illness that portended certain death after years—or even just months—of inexorable decline, infection with HIV has become a chronic, treatable illness. The advent of HAART in 1995 marked a critical turning point in the pandemic. Various combinations of potent medications, each targeting a different step in the virus's hijacking of its human host, reduced the incidence of the acquired immunodeficiency syndrome (AIDS) and improved life expectancy for many patients with HIV infection. Well into the fourth decade of the epidemic, now nearly 30 medications in five classes are available, at least in developed nations and increasingly in developing areas.

The successes of the past 30 years notwithstanding, diagnosis with HIV infection still foreshadows an arduous course of frequent examinations, serial monitoring of cell count and viral load, and difficult treatments with potentially disabling and disfiguring adverse effects (e.g., neuropathy, lipodystrophy). Effective treatment is not obtainable in all parts of the world, and, even in countries where medications are available, not all patients have access to them. At each step of what has been termed the HIV care cascade , significant attrition curtails the number of patients who receive the evaluation and care required to achieve the most critical outcome—full viral suppression. For example, in the US in 2009, 81.9% of HIV-infected people knew their status, 65.8% received care, 36.7% stayed in treatment, 32.7% received HAART, and only 25.3% achieved viral suppression. Blacks and Hispanics/Latinos were significantly less likely to be aware of their HIV status; young people were significantly more adversely affected at each level of the cascade. Closing these gaps in care will require overcoming several barriers, including health beliefs, mental illness, and stigma around HIV, sexual orientation, and substance use.

For the reasons listed in Box 57-1 , the general psychiatrist—regardless of venue and type of practice—will be called on to evaluate and to treat a fair share of patients with HIV infection. This chapter reviews the epidemiology, basic biology, classification, and diagnosis of HIV infection; a general approach to psychiatric care of HIV-infected patients; psychiatric and neurological disorders common in this population and their treatments; and special clinical problems encountered in HIV psychiatry.

Epidemiology

At the end of 2011, 34 million people were living with HIV infection worldwide. Sub-Saharan Africa remains the epicenter of the pandemic, followed by the Caribbean. In the US, at the end of 2011, 1.3 million people were living with HIV infection. Since 2001, approximately 50,000 new infections have occurred yearly. Of these, the largest proportion continue to occur in men who have sex with men (MSM).

Basic Biology

The HIV ( Figure 57-1 ) is a retrovirus—a virus containing ribonucleic acid and the enzyme reverse transcriptase for replication—that affects the immune system and the central nervous system (CNS), gaining entry to cells (e.g., Tlymphocytes, monocytes, macrophages) that express the CD4 receptor on their membranes. The life cycle of the virus once inside an infected cell is depicted in Figure 57-2 . All of the currently available antiretroviral medications target one of five key steps and enzymes in this process: fusion of the virus with the host cell membrane; entry into the cell; reverse transcriptase; integrase; and protease.

During the first weeks after infection, the population of CD4+ Tlymphocytes (i.e., the CD4 count) decreases as the amount of virus in the blood (i.e., the viral load) increases ( Figure 57-3 ). Following a weak and short-lived rebound, the CD4 count steadily declines. At the same time, the viral load oscillates around a “set-point” until ultimately viral replication intensifies and peripheral viremia surges. Administration of HAART, when effective, halts this process. Opportunistic infections (OIs), neoplasms, and neuropsychiatric conditions occur with increasing frequency as the immune deficiency worsens; prophylaxis for certain OIs (e.g., Pneumocystis jirovecii [formerly Pneumocystis carinii ] pneumonia and toxoplasmosis) is instituted during the course of infection according to the CD4 count.

Classification and Diagnosis

According to the Centers for Disease Control and Prevention (CDC), AIDS is defined by a CD4 count below 200 cells/µl (or less than 14% of total lymphocytes) or the presence of an AIDS-defining condition ( Box 57-2 ).

Infection with HIV is usually diagnosed in two steps. The initial test is an enzyme-linked immunosorbent assay (ELISA). A positive result on this test is then confirmed by a Western blot test. Because one-fifth of HIV-infected people in the US are unaware of their serostatus, the CDC and the United States Preventive Services Task Force (USPSTF) recommend that HIV testing be done as part of routine clinical care for all patients, regardless of risk factors.

General Approach to Psychiatric Care

The approach to the psychiatric care of the patient with HIV infection focuses on accurate diagnosis; an appreciation of the differences in response to, and tolerability of, psychotropic medications; and the prognostic importance of optimal adherence to effective antiretroviral treatment, which psychiatric illness often compromises.

Psychiatric symptoms in a patient with HIV infection may be primary or secondary ( Box 57-3 ); the CD4 count provides useful initial guidance in making this differential diagnosis. A CD4 count greater than 500 cells/µl suggests a primary psychiatric cause, whereas a CD4 count less than 200 cells/µl, and a fortiori less than 50 cells/µl, suggests the psychiatric problem is secondary to the effects of immune compromise. For example, a patient who has just been told that he is HIV-positive but whose CD4 count is still normal and whose viral load is low may become depressed as part of an adjustment disorder (a primary psychiatric problem). However, 10 years later, when he again has depressed mood and his CD4 count is 100 cells/µl, he may very likely have an OI or a neoplasm affecting his CNS and causing depression (a secondary psychiatric problem).

Distinguishing between primary and secondary causes has therapeutic implications because results of standard psychiatric treatment for secondary problems may be inferior to those achieved if the problem were primary. As in a patient with traumatic brain injury, stroke, dementia, or advanced age, the brain of a patient with HIV infection can be considered to be more sensitive to psychotropics and to have less reserve capacity. Thus a standard dose of a psychotropic medication may have a more (or less) profound effect in an HIV-infected patient or may cause adverse effects that usually occur only at higher dosages.

Optimum treatment of HIV infection and related conditions is essential for effective psychiatric care. Close collaboration between the psychiatrist and the physician providing the HIV care (usually a specialist in infectious diseases) is crucial.

Psychiatric Disorders