Treatment for Cocaine Addiction May Reduce HIV Risk
Cocaine addiction has previously been linked to an increased risk of contracting HIV, mainly as a result of sharing contaminated injection equipment, unprotected sex, exchange of sex for drugs, increased sexual drive from the stimulatory effects of cocaine, and impaired judgement. Although research has indicated that patients receiving treatment for heroin addiction have a decreased risk of HIV infection, few studies have focused on changes in HIV risk following treatment for cocaine addiction. Now, NIDA-funded researchers have found more evidence that participation in cocaine treatment may reduce the risk of HIV infection.
The researchers evaluated HIV risk among 487 cocaine-dependent patients that were recruited from five treatment programs participating in the NIDA Cocaine Collaborative Treatment Study. The multi-site trial examined the efficacy of four outpatient-based psychosocial treatments for cocaine dependence consisting of group drug counseling (GDC) alone and GDC in combination with individual drug counseling (IDC), cognitive therapy (CT), or supportive-expressive therapy (SE). Patients attended GDC weekly and individual therapy sessions for IDC, CT, or SE twice per week. At the end of screening and after 6 months of treatment, patients completed the Risk Assessment Battery, a standardized questionnaire that measures behaviors associated with HIV risk, such as drug use and high-risk sexual behaviors.
Prior to treatment, the average patient had used cocaine for 7 years and reported 10 days of cocaine use in the previous month. Crack smoking was the most common form of use. Seventy-nine percent of patients smoked crack, 19 percent snorted cocaine, and 2 percent injected the drug. HIV risk was mainly associated with high-risk sexual behaviors.
At the 6-month follow-up, cocaine use had decreased to an average of once per month. Patients receiving a combination of IDC and GDC showed the best improvements in reducing cocaine use compared to patients receiving CT and SE. Overall, the decrease in cocaine use was associated with a 40 percent reduction in HIV risk across all treatment, gender, and ethnic groups, mainly due to fewer sexual partners and less unprotected sex.
- WHAT IT MEANS: These findings indicate that treatment for cocaine addiction, including HIV-risk-reduction counseling, may be an effective strategy for preventing HIV infection.
Dr. George E. Woody and colleagues from the University of Pennsylvania and the Department of Veterans Affairs Medical Center in Philadelphia published the study in the May issue of the Journal of Acquired Immune Deficiency Syndromes.
Study Finds Link between Inflammatory Protein and Heart Disease Among Cocaine Users
Cocaine use has been associated with a number of cardiovascular complications, including artery blockages and heart attacks. In a recent study, NIDA-funded scientists have helped to identify the effects of cocaine use that may lead to heart problems. They found that in cocaine abusers, elevated levels of serum C-reactive protein (CRP)—a protein associated with inflammation—were associated with endothelial abnormalities and coronary artery calcification, which are factors known to contribute to heart disease.
Fifty-three African-American adults from Baltimore, Maryland, between 25 and 45 years of age with a history of cocaine use were recruited to participate in the study. The researchers conducted a variety of tests, including an echocardiographic examination, spiral computed tomography (CT) scans to look for coronary calcification, analysis of blood for serum cholesterol and CRP, and an evaluation of endothelial function.
The researchers found that 45 percent of the participants had serum CRP levels above the normal range of the general population. Those with elevated CRP had greater endothelial abnormalities and more coronary calcification than those with normal CRP levels.
- WHAT IT MEANS: CRP may be a marker of future cardiovascular events. The findings in this study suggest that many chronic cocaine users have elevated levels of serum CRP, which are associated with subclinical coronary atherosclerosis and cardiac abnormalities. This study provides more evidence that cocaine use may contribute to the development of coronary artery disease.
This study was published by lead investigator Dr. Shenghan Lai at Johns Hopkins University in the April 2003 issue of the International Journal of Cardiology.
HIV Patients Who Are Older, Free of Cognitive Deficits, And Do Not Abuse Drugs Comply Better with Medication Schedules
In a study to assess the effects of age, substance abuse, and neuropsychological function on adherence to antiretroviral treatment among HIV-infected adults, researchers found that patients over the age of 50 who did not abuse drugs and who were free of cognitive impairment had the best adherence rates.
Medication adherence is critically important for HIV infected adults. Studies have shown that good adherence (typically defined as 90-95 percent of doses taken as prescribed) has been linked to improved health status and reduced mortality rates. Patients who do not meticulously adhere to the medication regimen are at risk for a worsening of their HIV disease, including possibly developing strains of the virus that no longer respond to standard HIV medications.
The investigators tracked medication usage over a one-month period in 148 HIV-infected individuals between the ages of 25 and 69, all of whom were on a self-administered antiretroviral regimen. All of the participants were tested for HIV-related cognitive impairment that can include memory problems, difficulties with planning and judgement, and a slowing of the brain’s ability to process information.
Patients over the age of 50 were three times more likely to be properly adherent to their medication schedule—defined as taking 95 percent of the prescribed medications—than were younger patients. Fifty-three percent of the patients over 50 achieved this standard compared to 26 percent of the younger patients.
Testing showed that 83 percent of the patients over the age of 50 who had poor adherence to the medication regimen had some cognitive impairment. Current drug abuse was also associated with poor medication adherence. More than 90 percent of the patients who were current drug abusers failed to adequately adhere to the medication regimen.
- WHAT IT MEANS: This study documents the importance of assessing cognitive function—particularly among older patients—and drug abuse status when treating HIV-infected adults. In order to maximize compliance, the medication regimen may need to be simplified or assistance may need to be provided for those found to have cognitive impairments.
A research team led by Dr. Charles Hinkin of the David Geffen School of Medicine at UCLA and the VA Greater Los Angeles Health Care System conducted this study with funding provided by the National Institute on Drug Abuse and the National Institute of Mental Health. The findings were published in the December 24, 2002 issue of the journal Neurology and will appear in an upcoming special issue of the journal AIDS.
Immigrant Status and Country of Origin Important in Compiling Smoking Prevalence Statistics
Using the 1995-96 and 1998-99 Current Population Survey (CPS) Tobacco Use Supplements, researchers found that smoking prevalence was higher among people born in the United States than among their racial and ethnic counterparts who were foreign-born.
Furthermore, smoking prevalence varied by country of birth for immigrants. For example, smoking prevalence among Asian and Pacific Islander immigrants as a whole was 11.8 percent. Yet when country of origin was considered, smoking prevalence rates ranged from 4.6 percent among Indian immigrants to 21.4 percent among Japanese immigrants.
According to the CPS Tobacco Use Supplements, an estimated 21.6 percent of the American public smokes, but when desegregated by immigrant status, the figures show that native-born respondents had higher smoking rates than foreign born—22.6 percent versus 13.4 percent. Smoking prevalence statistics broken down without regard to immigrant status show that the highest smoking prevalence was reported among American Indians (33.2 percent), followed by Whites, non-Hispanic (22.7 percent), Blacks (20.9 percent), Hispanics (15.5 percent) and Asian and Pacific Islanders (12.7 percent).
- WHAT IT MEANS: By ignoring immigrant status, smoking prevalence statistics may hide segments within broadly defined racial and ethnic groups that have vastly different smoking behaviors than the aggregated group. Including findings about country of origin and immigrant status can greatly enhance the development of targeted and culturally sensitive smoking cessation programs.
Dr. Kaari Flagstad Baluja, Julie Park and Dr. Dowell Myers conducted the research under the auspices of the Transdisciplinary Tobacco Use Research Center at the University of Southern California. The study was published in the April 2003 issue of the American Journal of Public Health.
Behavioral Treatment May Reverse Brain Changes that Occur with Cocaine Use and Help Prevent Relapse
Brain changes that occur with cocaine use and the tendency toward relapse may be reduced by a behavioral treatment using extinction training—a form of conditioning that removes the reward associated with a learned behavior. NIDA-funded researchers found that extinction training during cocaine withdrawal produces changes in brain receptors for glutamate, a brain chemical found in the nucleus accumbens, the reward center of the brain. A reduction in glutamate input from cortical brain regions by chronic cocaine use is thought to contribute to persistent cravings for the drug.
The researchers trained rats to self-administer cocaine by pressing a lever and to associate the availability of cocaine with certain environmental cues (lights and noise). Once the rats had learned to expect cocaine when they pressed the lever, cocaine and the cues were removed so that the rats did not receive the cocaine that they were anticipating. One group of rats received this extinction training during cocaine withdrawal while another group did not receive the training. After extinction training was over, the researchers exposed the rats to the cocaine-associated cues and administered cocaine to induce relapse.
The researchers found that the rats given extinction training during withdrawal had more than a 30 percent increase in glutamate receptors in the outer regions of their nucleus accumbens. The number of glutamate receptors did not increase in rats that did not receive the training during withdrawal. When cocaine-related cues were reinstated, rats showing relatively no response to these stimuli had a greater increase in receptors than rats that responded to the cues.
- WHAT IT MEANS: These findings indicate that behavioral-based treatment approaches have the potential to reverse or lessen the harmful neurobiological and behavioral consequences of chronic drug use. Increasing the number of glutamate receptors may help ease cravings for cocaine during abstinence and also help prevent relapse.
This study was published by lead investigator Dr. David Self at the University of Texas Southwestern Medical Center in the January issue of Nature.