Cannabis clinical trials at UCSD

The American Academy of Pain Medicine has labeled pain as a "silent epidemic" due to its staggering costs to society (over $500 billion/year) and widespread prevalence (affects over 100 million Americans). Thus, it is imperative to test and validate cost-effective pain therapies. To this extent, cannabis is characterized as one of the most promising therapies to treat a wide spectrum of pain conditions. However, the clinical applicability of cannabis-based pain therapies has been limited due to lacking mechanistic characterization in human-focused studies. Of critical importance, the neural mechanisms supporting cannabis induced pain relief remain unknown. The primary objective of the proposed pilot study is to identify the brain mechanisms supporting the direct alleviation of acutely evoked pain through vaporized cannabis.

This study will address whether cannabis affects antiretroviral therapy (ART) drug concentrations, mood, and thinking. The project will have two phases. Phase 1 is an observational study, in which 120 people will be assessed to evaluate the effects of chronic cannabis use on ART drug concentrations, mood, and thinking. In Phase 2, the study will administer cannabis (or placebo) to 40 people to examine its acute effects on ART drug concentrations.

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.

This study has the potential to contribute to a more complete understanding of the independent and combined effects of cannabis use and HIV on the brain and on inflammation. Such knowledge may inform future strategies for treating brain disease and inflammation. Participants will be randomly assigned to one of two groups, both of which will receive the same treatment in a different order over a period of about 6 weeks. The visits include physical examinations, blood tests, and other procedures designed to monitor subject safety and measure the effects of the study drug.