Most estimates suggest that there are just over a million persons living with HIV/AIDS in the United States.1 According to CDC data, between 2001 and 2005, an average of 37,127 new cases of HIV infection, HIV infection and later AIDS, and concurrent HIV infection and AIDS were diagnosed each year.2 Injection drug use, male-to-male sexual contact in men and adolescent boys, and high-risk heterosexual contact in women and adolescent girls are the 3 most common routes of transmission.2 Among individuals with psychiatric illness, injection drug use and other high-risk behaviors contribute significantly to high rates of HIV infection.
In the early 1980s, a number of young men died of infections that were usually only seen in immune-compromised patients. Over the next several years, the HIV virus was identified, characterized, and found to be an RNA virus that was only transmitted by intimate contact, most commonly sex and shared needles. The public health response to the epidemic seemed obvious at the time, and a campaign to educate people at risk about the use of condoms and clean needles was launched. It was surprising to many public health officials that the epidemic continued but less surprising to those who worked in mental health areas and already knew how difficult it is to change behaviors.
The devastation that originally brought mental health professionals to HIV clinics to help with the losses and sadness related to patient deaths gave way to the need for mental health professionals to treat the psychiatric disorders that were associated with the continued high-risk behaviors in psychiatric subpopulations. Depression, mania, impulsivity, substance abuse, intoxication, cognitive impairment, and personality vulnerabilities are all associated with risk of HIV infection.
As an example, in the HIV clinic at Johns Hopkins, which serves about 3000 predominantly indigent and minority patients, we evaluated all new patients coming for medical care in the early 1990s and found that 54% had an Axis I disorder other than substance abuse, and that 74% had a substance use disorder. There were high rates of major depression (20%) and cognitive impairment (18%).3 Later work showed that chronically mentally ill patients were at increased risk for HIV infection. The seroprevalence of HIV infection among the mentally ill is estimated to be 3.1%,4 much higher than the seroprevalence estimate of 0.3% in the general US population.5
Data from the National Treatment Improvement Evaluation Study indicate that the prevalence of HIV among patients with dual diagnoses of severe mental illness and substance abuse is 4.7%, which is much higher than the prevalence of 2.4% in patients with a single diagnosis of substance abuse.6 Patients with dual diagnoses are more than twice as likely to have HIV infection as patients who have a single diagnosis. This is true of older patients as well as younger. In a national sample of veterans in the Veterans Affairs health system in the 2002 fiscal year, researchers determined that the prevalence of HIV infection was twice as high among patients with severe mental illness as it was in patients who did not have severe mental illness.7
In the mid-1990s came the discovery that combination therapy could essentially halt the progression of HIV infection; thus, HIV infection became a chronic disease. This development was a miraculous reversal of the inevitable fatal course that patients had faced only months earlier. The problem was that patients had to take 90% of their medications to prevent progression and the development of viral resistance, and many patients were unable to adhere to the requirements of treatment. Research quickly confirmed that the same psychiatric risk factors that increased transmission of HIV also interfered with the adherence to treatment with antiretroviral cocktails.
Not only does mental illness increase the risk of infection with HIV, but the presence of HIV/AIDS increases the lifetime prevalence of psychiatric illness.8 The relationship between HIV/ AIDS and psychiatric illness increases the severity of illness in either case, with resultant exacerbation of other medical comorbidities. The diagnosis and management of psychiatric illness in HIV/ AIDS is complicated by patient nonadherence to psychiatric treatment and/or HIV treatment.Depression
Major depressive disorder (MDD) is a common and well-studied psychiatric disorder in patients who are HIV positive. During their lifetime, 22% to 45% of patients living with HIV/AIDS will experience depression compared with 5% to 17% of the general population.9,10 The diagnosis of depression in the context of HIV/AIDS can be a challenge because symptoms of fatigue, decreased appetite and libido, and poor memory are also symptoms of HIV infection. In particular, this is of more importance in older persons with HIV/ AIDS.11 No difference exists between the lifetime prevalence of depression among young and older individuals with HIV/AIDS; in the general population, current and lifetime depression decrease with age.12
Depression is intimately related to HIV infection. Patients with MDD tend to have increased risk-taking behavior and substance use. HIV transmission or acquisition is more likely to result from risky behavior in depressed individuals than in those who are not depressed. Risky behavior includes increased number of lifetime sex partners, having sex with injection drug users, having sex while intoxicated, and having sex for money or drugs.13 Psychiatric patients with depressive disorders who are substance abusers are at higher risk for HIV infection than are psychiatric patients with another diagnosis.14
HIV infection increases the risk of depression. While depressive symptoms may appear as a reaction to a new diagnosis of HIV infection,15 there is also evidence that advancing HIV infection increases depression directly.16
A proposed mechanism of the interrelationship between HIV infection and MDD might be a decrease in cobalamin in the brain associated with HIV infection, which increases the risk of MDD. This is also associated with supression of natural killer cells and CD8 T cells, thereby worsening HIV infection.17 Another suggested mechanism is that HIV infection increases the risk of depression by reducing serotonergic transmission in the brain.18
Depression is also associated with higher rates of nonadherence to medication regimens.19,20 Symptoms of depression, such as apathy, lack of interest in self-care, and loss of concentration may result in patients ignoring symptoms and not keeping clinical appointments, which in turn, may contribute to disease progression and increased mortality. When clinical correlates of HIV infection are controlled for, patients who are depressed have a 2-fold increase in mortality.21 Similarly, improved outcomes, such as increased CD4+ cell counts, decreased hospitalization, and AIDS-related mortality are associated with adherence to medication schedules.22,23
There is no evidence that one antidepressant is superior to another in treating MDD in HIV/AIDS patients, but there is ample evidence that antidepressants are effective in these patients.