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

INTRODUCTION: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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.