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Past Studies:


This randomized controlled trial examines the efficacy of a computerized cognitive training program to improve working memory and reduce delay discounting in persons living with HIV who use stimulant drugs like cocaine. The sample includes 50 HIV-positive adults who use cocaine and have impairment in working memory. After completing an eligibility screen, participants are assigned to one of two groups: active cognitive training or control training (25/group). The web-based computerized cognitive training program includes 48 training sessions completed over 8 weeks. To evaluate the impact of the training program, participants complete assessments at baseline, post-training, and 1-month follow-up. The goal of the project is to obtain empirical support for a low-cost intervention to improve neuropsychological functioning and clinical outcomes in HIV-positive cocaine users. (ClinicalTrials.gov Identifier: NCT02909101)

Funding: R21-DA039016 (Meade PI)


IMPACT Pilot Study

Funded by the Duke Center for AIDS Research, this study examined the efficacy of a brief cognitive training intervention on improving working memory in persons living with HIV. The sample included 21 adults who are HIV-positive. After completing an eligibility screen, participants were assigned to one of two groups: active cognitive training or control training. Participants completed 12 training sessions across 10 weeks using a computerized cognitive training program, and completed assessments at baseline and post-training to evaluate the impact of the training program. The goal of the project was to obtain empirical support for a low-cost intervention to improve neuropsychological functioning in persons living with HIV. (ClinicalTrials.gov Identifier: NCT02216591)

Funding: P30-AI064518 (Towe Project PI)


Project MIND

Marijuana is the most common drug of abuse among HIV-infected persons in the United States. Previous research has documented that marijuana and HIV independently disrupt functioning in the fronto-parietal “executive control” network of the brain, and white matter damage is an integral part of HIV-associated neuropathology. However, the interactions of marijuana and HIV on brain functioning and structure have not been well characterized. This project combined multi-modal magnetic resonance imaging (MRI) and neuropsychological assessment to test whether marijuana use and HIV infection have synergistic effects on neurocognitive impairment, specifically in executive control functions, and how differences in brain function and structure relate to neurocognitive impairment. Using a case-control design, we assessed 60 adults across four study groups who differed on marijuana and HIV status (15/group). The specific aims were to examine white matter integrity using diffusion tensor imaging (DTI), functional connectivity using resting state functional MRI (RS-fMRI), and the relationship between neurocognitive impairment and these MRI data. The overarching goals of this research were to elucidate brain regions affected by marijuana and HIV that contribute to observed neurocognitive impairments in HIV-infected marijuana users. As a supplement to Project MIND, Dr. Hobkirk received a scholar award from the Mount Sinai Institute for NeuroAIDS Disparities to identify social and economic determinants of executive control for racial and ethnic minorities living with HIV.

Funding: R03-DA035670 (Meade PI), R25-MH080663 (Morgello PI)


Project DECIDE

HIV-related decision making, like most real-world decisions, involves the valuation of potential gains and losses in the context of uncertain outcomes. Cocaine dependence and HIV infection can each disrupt brain circuits that regulate executive functions involved in decision making. This project combined functional neuroimaging, behavioral risk assessment, and computational modeling to isolate the effects of cocaine dependence and HIV infection on decision making processes, specifically loss aversion and ambiguity tolerance, and to examine the relationship between these decision making processes and sexual risk behavior. Using a case-control design, we examined behavioral choice and brain activity during monetary gambles that varied independently on the value of gains and losses and the certainty of outcomes. The sample included 80 adults who differed on cocaine and HIV status, comprising four distinct groups (20/group). Results of this study provide unique insights into the mechanisms underlying HIV-related decision making.

Funding: R21-DA036450 (Meade PI)


Project Brain Reloaded

Both HIV infection and stimulant abuse affect neurocognitive functioning, yet few studies have empirically examined the effects of co-occurring HIV infection and stimulant abuse on neurobehavioral outcomes. The study aimed to: (1) identify patterns of neurocognitive impairment in HIV infection and cocaine dependence, and test whether these are associated with risky decision making and behavioral risk; and (2) examine brain activation patterns associated with decision making as a function of HIV disease progression and co-occurring versus independent HIV infection and cocaine dependence. Using a case-control design, 200 individuals stratified by HIV and cocaine status completed a battery of neurocognitive and behavioral measures. A subset (20-25 per group) participated in an fMRI experiment to examine brain activity during decision tasks.

Funding: K23-DA028660 (Meade PI)


Carolina Connections

This study assessed the feasibility of using respondent driven sampling with individuals from the Raleigh-Durham area. The goal was to engage new members of the community to research studies at HARP by using a chain referral strategy that encourages participants to refer others in their social network. In addition, the study aimed to examine how social determinants impact lab-based decision making and real-world health outcomes.

Funding: F32-DA038519 (Hobkirk PI)



South Africa, particularly the Western Cape, has experienced a dramatic rise in methamphetamine use since early 2000 and also has the largest number of HIV-infected individuals of any country in the world. It is feared that methamphetamine use may further fuel this HIV epidemic because of its association with risky sexual behaviors. This mixed-methods study characterized the patterns and severity of drug addiction in a sample of 360 methamphetamine users in Cape Town, South Africa, and identified predictors of HIV sexual risk behavior in this population. As a secondary goal, we tested the feasibility of using respondent driven sampling (RDS) to recruit methamphetamine users in HIV behavioral research trials.

Funding: R03-DA033028 (Meade PI)



This study examined HIV risk among nearly 300 methamphetamine users seeking drug abuse treatment in two township communities. Specific aims were to: evaluate HIV seroprevalence at clinic intake, describe the prevalence  and correlates of sexual risk behaviors, and identify opportunities to integrate primary and secondary HIV prevention into addiction treatment for this population.

Funding: P30-AI064518 (Meade Project PI)


Project MANIC

The purpose of this study was to examine impulsivity, drug abuse, and sexual risk behavior in individuals with HIV infection and mood disorders. The study aims were to: (1) examine trait-like and behavioral impulsivity in HIV patients with bipolar disorder (BD), major depression (MDD), and no psychiatric disorder (NPD); (2) assess the relationship between impulsivity and sexual risk; (3) test whether BD patients engage in higher rates of sexual risk, and whether impulsivity mediates this relationship. In this observational study, approximately 75 HIV-infected adults with BD, MDD, and NPD (25/group) completed a battery of self-report and measures of impulsivity, substance abuse, and sexual risk. Assessments included clinical interviews, questionnaires, and experimental tasks.


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