Understanding how co-morbidities in persons with HIV (PWH) such as substance use affect risk-taking, decision-making, and other cognitive behaviors is important given implications for everyday functioning and transmission risk. The high prevalence of cannabis use in PWH, medicinally and recreationally, may indicate disease severity, impart therapeutic benefits, or adverse consequences. In fact, cannabis is recommended to those with HIV to alleviate nausea, improve appetite, relieve pain, and lift mood. To-date, the consequences of cannabis use in PWH remain unclear as do potential interactions with HIV treatments. In healthy participants, heavy cannabis use is associated with cognitive deficits e.g., risky decision-making, response disinhibition and inattention, but pro-cognitive effects in PWH may exist at mild use levels due to its anti-inflammatory and anti-excitotoxic properties. Furthermore, little has been done to determine the effects of cannabis use on the endocannabinoid (EC) system in general or in PWH. This study will determine the effects of the two primary cannabis constituents (Δ9-tetrahydrocannabinol [THC], cannabidiol [CBD]) vs. placebo on risky decision-making, response inhibition, reward learning, temporal perception, and motivation, plus EC and homovanillic acid (HVA; a surrogate for dopamine activity) levels in HIV+ and HIV- subjects. Participants with infrequent cannabis use will undergo baseline cognitive testing and biomarker assays with antiretrovirals (ART) use quantified. They will be randomized to a 5-day course of either THC, CBD, or placebo and return for follow-up testing and re-assaying of ECs and HVA levels.
