JDP student, Caitlin Wei-Ming Watson

Caitlin Wei-Ming Watson and UC San Diego colleagues were featured in a San Francisco AIDS Foundation news article on their paper “Cannabis exposure is associated with a lower likelihood of neurocognitive impairment in people living with HIV.”

“Cannabis use may be associated with less HIV-related cognitive impairment, suggests new research from Caitlin Wei-Ming Watson and colleagues at the University of California, San Diego. The study, which included about 1,000 adults with varying histories of cannabis use, found lower rates of difficulties with learning and verbal fluency in people living with HIV who used cannabis.

‘Recent research shows that cannabinoids have anti-inflammatory properties,’ said Watson. ‘We hypothesized that some degree of cannabis exposure may be protective for brain health in certain contexts. While in the general population, heavy cannabis use is associated with null or negative cognitive outcomes, we were interested in whether cannabis would show different effects on cognition in a disease like HIV, which is characterized by a weakened immune system and persistent inflammation.’

Further research is needed to clarify what aspects of cannabis are therapeutic or not therapeutic—including the effect of dose, frequency of use and type of cannabis product. Watson stated that their findings have several limitations. ‘Our study was retrospective and did not capture detailed information about cannabis use such as potency, nor did we capture important factors such as psychosocial context, including motivations for cannabis use. There also may be other negative health consequences of heavy long-term cannabis smoking such as chronic bronchitis which are important to keep in mind.’

‘In the future, we would like to be able to define what levels of cannabis exposure are linked to optimal brain and cognitive health, and what levels may be detrimental,’ said Watson. ‘It is likely that beneficial effects are limited to certain dose and frequencies of use, and also vary by cannabis compound (e.g., THC vs. CBD vs. CBC).’ At this point, we don’t want the take-away to be, ‘If you have HIV, you can use cannabis and that’s going to be really good for your brain health and cognition.’ We need to do much more research before we can make more specific recommendations regarding the impact of cannabis use on the brain in HIV disease’

Watson CW, Paolillo EW, Morgan EE, Umlauf A, Sundermann EE, Ellis RJ, Letendre S, Marcotte TD, Heaton RK, Grant I. (2020). Cannabis exposure is associated with a lower likelihood of neurocognitive impairment in people living with HIV. Journal of Acquired Immune Deficiency Syndromes, 83(1), 56-64.

Scientific article at JAIDS: https://pubmed.ncbi.nlm.nih.gov/31809361/