The Impact of Crystal Methamphetamine Use on HIV-Positive Individuals
"Crystal" is the popular street name of the pharmaceutical compound methamphetamine. The drug is a potent psycho-stimulant that has the potential to cause irreparable physical, psychological, and social damage to individuals who abuse or become dependent on this substance. Use of this illicit drug is found among all sectors of American society, is equally used by both men and women, in rural and urban settings, and across races and ethnicities. Also known as "crank," "meth," "Tina," and "ice," the drug has been abused by Americans for over 50 years.
Given the strong association between use of the drug and sexual risk taking, especially among gay and bisexual men where HIV is highly concentrated, concerns about the drug have extended beyond the addiction, creating the potential for a "dual epidemic."For example, in 2003, The San Francisco Chronicle reported that over 40% of gay men in San Francisco had tried crystal methamphetamine, and that close to one-third of new HIV seroconversions occurred in men who had used the drug in the recent past. These patterns have also been noted in other large gay centers such as New York City, Miami, and Atlanta. Because of the intimate link that exists between abuse of methamphetamine and HIV sexual risk-taking, Gay Men's Health Crisis (2004) convened task forces and implemented educational strategies to address the rising use of the drug.
Effects of Methamphetamine Abuse
Abuse of and addiction to methamphetamine may have many pronounced effects on the user as well as the individual's family and friends. For example, Brecht et al. (2004) found that in a sample of 350 individuals recruited from a publicly funded treatment site, 84% reported weight loss due to their methamphetamine use.Other problems included sleeplessness (78%), financial problems (73%), paranoia (67%), legal problems (63%), hallucinations (61%), work problems (60%), violent behavior (57%), dental problems (55%) and skin problems (36%). Methamphetamine abuse complicates an individual's life, not only causing potential for irreparable physiological damage and potential death, but also deterioration in one's cognitive, emotional and social stability. The effect of the abuse of methamphetamine on sexual behavior can also act as a lubricator or facilitator for the transmission of HIV and other pathogens. Finally, there is abundant evidence of the cardiovascular, neurological, psychiatric, and oral complications associated with chronic use of methamphetamine.
Methamphetamine Addiction and Sexual Risk Taking
The extant literature supports the association between use of methamphetamine and the transmission of HIV, especially among gay and bisexual men. Behavioral research has documented the association between the use of methamphetamine and the heightening of sexual behavior in gay and bisexual men.Use of the drug is layered with complex behavioral and psychologically driven motivations (e.g., desire for socialization, sexual promiscuity, decreased loneliness, and depression). Such associations are also evident in non-gay populations. However, because HIV continues to permeate the gay male population more than any other in the United States, much of the behavioral research on methamphetamine use and sexual risk taking has focused on this affected group.
On average, sexual behavior under the influence of crystal is related to higher sexual risk. For example, Mansergh et al. (2006) estimated that methamphetamine use doubled the likelihood that men who have sex with men engage in unprotected receptive anal intercourse. Among gay men with unknown HIV status, methamphetamine use was associated with 18 times more unprotected receptive anal intercourse in men who eventually tested HIV-positive compared to those who were HIV-negative. Similarly, Wong et al. (2006) delineated that methamphetamine use increased the likelihood of contracting syphilis 6-fold, and Plankey et al. (2007) indicated that there was a 1.46 increase in relative hazard for HIV seroconversion associated with methamphetamine use.
Like all other behaviors which burden the bodily system, the use of methamphetamine may have particularly pronounced effects for HIV-positive individuals. This is due in part to the adulterated nature of illegally produced crystal methamphetamine, which often contains lead and may be "cut" with other materials that can be damaging to those with lower functioning immune systems. "Drug seizures show an average purity of 54%, diluted with ingredients such as baking soda, lactose, Epsom salts, quinine, mannitol, procaine, ether, insecticides, MSG, photo developer, and strychnine." In addition, the impact of the drug on the cardiovascular, pulmonary, and neurological systems may be more pronounced for those who are HIV-positive.
Adverse interactive effects of HIV medications and methamphetamine have been noted, in particular, with individuals who have been undergoing treatment with the HIV antiviral, Ritonavir. Furthermore, methamphetamine use interferes with adherence to HIV antiviral treatments. Halkitis et al. (2002) showed that gay and bisexual men who indicated the use of methamphetamine also indicated a greater number of missed doses of their protease inhibitor treatment than those who did not indicate use of the drug (12 missed doses vs. 4 missed doses per 2 month period). Ellis et al. (2003) demonstrated that active methamphetamine-using HIV-positive persons have higher viral loads than those who never used the drug or recently used the drug. But the impact of methamphetamine on the effectiveness of antiviral therapies may be undermined even in the presence of optimal adherence. Specifically, Ahmad (2002) indicated that even with optimal adherence, use of the drug was associated with greater HIV viral replication in the brain. Similarly, Gavrilin et al. (2002), and Carrico et al. (2007) documented a five-fold higher viral load among those who reported regular stimulant (including methamphetamine) use than those who did not use stimulants.
One of the most pronounced effects of methamphetamine use is its impact on the neurotransmitter systems, especially those systems which control the release of dopamine. Dopamine is the neurotransmitter which creates pleasurable feelings, and in the presence of methamphetamine use, is released at heightened rates and is not fully reabsorbed by neurons, leading to a great sense of euphoria. However, the synergistic effects of HIV and methamphetamine on the dopaminergic system may increase the HIV-positive user's susceptibility to neurotoxicity. The interaction between methamphetamine abuse and HIV infection may cause alterations in the size of certain brain structures. In both cases, the changes may be associated with impaired cognitive functions, such as difficulties in learning new information, solving problems, maintaining attention, and quickly processing information. To this end, the comorbidities of methamphetamine abuse/addiction and HIV infection result in greater impairment in this neurological system than is engendered by each condition in isolation. In a comparison of the interactive effects of methamphetamine use and HIV infection, Rippeth et al. (2004) examined the interactive effects of methamphetamine use and HIV infection on cognitive functioning. The data demonstrated that rates of impairment to global neuropsychological functions were highest among HIV-positive methamphetamine users (58%), followed by HIV-negative methamphetamine users (40%), HIV-positive non-methamphetamine users (38%), and were lowest among HIV-negative, non-methamphetamine users (18%), indicating the synergy between HIV infection and abuse of the drug.
In addition to the interactive effects of HIV and methamphetamine use in neural systems, this comorbidity has other physiological implications resulting in the development of opportunistic infections. In one study, Tallóczy et al. (2008) found that methamphetamine directly affects the ability of the body to effectively combat infections by exerting an immunosuppressive effect on dendritic cells and macrophages. Use of methamphetamine may exacerbate the replication and inhibit the intracellular destruction of two AIDS-related pathogens -- Candida albicans, the fungal infection that effects the gastrointestinal systems, a.k.a. "thrush", and Cryptococcus neoformans, the fungus that can cause meningitis in HIV-infected individuals.
Data suggest that a subset of HIV-positive individuals are often users of this drug, especially gay and bisexual men. For the immuno-compromised person in particular, the administration of methamphetamine may have even more severe effects. In addition to exacerbating the potential for the transmission of HIV to sexual partners, the substance itself has significant effects on the biological system of the seropositive individuals, including neurological complication and associated increase in viral replication. Special attention needs to be paid to the physical and mental health of HIV-positive individuals who are using, who are recovering from use, or are at risk for initiating the use of methamphetamine. Health care providers should be keenly aware of signs of addiction to methamphetamine, and work openly and honestly with their patients to address the detrimental effects of methamphetamine addiction.