Background: The most robust neurocognitive effect of marijuana use is memory
impairment. Memory deficits are also high among persons living with HIV/AIDS, and marijuana is
the most commonly used drug in this population. Yet research examining neurocognitive outcomes
resulting from co-occurring marijuana and HIV is limited.
Objective: The primary objectives of this comprehensive review are to: (1) examine the literature on
memory functioning in HIV-infected individuals; (2) examine the literature on memory functioning
in marijuana users; (3) synthesize findings and propose a theoretical framework to guide future
Method: PubMed was searched for English publications 2000-2013. Twenty-two studies met
inclusion criteria in the HIV literature, and 23 studies in the marijuana literature.
Results: Among HIV-infected individuals, memory deficits with medium to large effect sizes were
observed. Marijuana users also demonstrated memory problems, but results were less consistent due
to the diversity of samples.
Conclusion: A compensatory hypothesis, based on the cognitive aging literature, is proposed to
provide a framework to explore the interaction between marijuana and HIV. There is some evidence
that individuals infected with HIV recruit additional brain regions during memory tasks to
compensate for HIV-related declines in neurocognitive functioning. Marijuana is associated with
disturbance in similar brain systems, and thus it is hypothesized that the added neural strain of
marijuana can exhaust neural resources, resulting in pronounced memory impairment. It will be
important to test this hypothesis empirically, and future research priorities are discussed.