Cannabis use frequency may differentially impact cognitive performance in young adults with and without HIV

Increased cannabis use in young adults may influence brain health and neurodevelopment. In the context of chronic HIV-associated neuroinflammation, however, mild cannabis use may attenuate negative outcomes through anti-inflammatory effects. More frequent cannabis use may remain deleterious to both young adults with HIV (YWH) and without HIV (YWoH). We explored cross-sectional associations between cannabis use frequency and cognitive performance in YWH and YWoH.

Participants aged 18-24 included 38 YWH and 61 YWoH (32% White) who completed cognitive tests of verbal memory, processing speed, working memory, executive functions, and overall fluid cognition. Timeline follow-back interviews assessed days of cannabis use (past 30, 180 and 365 days). Primary analyses focused on 30-day use, categorized as: no use, mild/moderate (1-<5 days used/week) and heavy (≥5 days used/week). Generalized estimating equations modeled associations of HIV, cannabis use category, and their interaction with cognitive outcomes; trend analyses used cannabis frequency as a continuous variable. Due to group differences in proportion of females, sex differences could not be addressed.

YWH had worse performance than YWoH in fluid cognition, memory, processing speed, and executive functioning. Adjusting for HIV status, heavy 30-day use, versus no use, was associated with worse performance on fluid cognition, immediate and delayed word list recall, processing speed and executive functions. Relative to mild/moderate use, heavy use was associated with worse immediate and delayed story recall and executive functions. Results were similar for 180- and 365-day use. Interactions between HIV status and 30-day cannabis use category were not significant, although exploratory analyses employing cannabis use as a continuous measure suggested a linear relationship for YWoH of greater use with worse cognitive performance, while for YWH, non-linear relationships suggested better performance with mild/moderate use on some memory and executive functioning measures.

These results suggest ongoing heavy cannabis use is associated with worse cognitive performance among young adults. For YWH, however, mild to moderate levels of cannabis use may have a protective effect possibly through altering chronic neuroinflammation, although causality cannot be determined in this cross-sectional study. Understanding differential, population-specific effects of cannabis use frequency may be important in setting use guidelines.