THC Had Mixed Cognitive Effects in Rats With HIV-Like Disease | Research

The takeaway

In a rat model of HIV, THC improved learning performance but worsened risk-based decision-making, mirroring the mixed cognitive effects of cannabis seen in people living with HIV.

Researchers studying cannabis and HIV, clinicians treating people living with HIV who use cannabis

Learning improved, decision-making worsened with THC in HIV model

What the researchers found

Both acute and chronic THC exposure produced function-dependent effects in HIV-1 transgenic rats: learning improved but risk-based decision-making worsened. These effects were specific to HIV model rats and not seen in controls, suggesting THC interacts differently with HIV-affected brains.

Why it matters

Many people living with HIV use cannabis, and cognitive impairment is common in this population. Understanding that THC may help some cognitive functions while hurting others could inform clinical guidance.

The numbers in context

THC doses: 0.3 and 3 mg/kg. HIV-1 transgenic rats showed enhanced learning but worsened risk-based decision-making with THC. At baseline, HIV rats took longer to make decisions but performed normally, suggesting a speed-accuracy trade-off.

How the study worked

Female and male HIV-1 transgenic rats and controls were tested on two cognitive tasks: the rat Iowa Gambling Task (risk-based decision-making) and Probabilistic Reversal Learning Task (learning/cognitive flexibility). Testing occurred at baseline, then after acute and chronic THC (0, 0.3, 3 mg/kg IP).

What this study cannot tell us

Animal model doesn't fully replicate human HIV. IP injection doesn't mimic typical human cannabis use. The HIV-1 transgenic rat lacks active viral replication. Results may not directly translate to human cognitive outcomes.

How to read the evidence

Preliminary: animal study using a transgenic rat model that approximates but doesn't replicate human HIV

When this study was published

Published in 2025

The bigger picture

Cannabis effects on cognition are not uniform across brain functions. For people with HIV, THC might support certain types of learning while impairing judgment in risky situations, adding nuance to the debate about cannabis use in HIV.

Questions still open

Would CBD modify these effects? Do these function-specific patterns appear in human studies of cannabis and HIV? Does the dose-response curve differ for learning vs. decision-making?

Common questions

Does this mean cannabis helps or hurts cognition in HIV?

Both, depending on the cognitive function. THC improved learning ability but worsened risk-based decision-making in HIV model rats, suggesting the effects are task-dependent rather than uniformly good or bad.

Why did THC only affect the HIV rats and not the controls?

The HIV transgenic rats have neuroinflammation and altered brain chemistry that appears to change how THC interacts with cognitive circuits. Healthy rat brains were not affected the same way at these doses.

Read the original research

Beneficial and adverse effects of THC on cognition in the HIV-1 transgenic rat model: Importance of exploring task- and sex-dependent outcomes.

Brain, behavior, and immunity, 128, 571-588

View on PubMed ↗Publisher’s paper ↗

Citation

Ayoub, Samantha M; Vemuri, Sunitha; Hoang, Elizabeth B; Jha, Neal A; Minassian, Arpi; Young, Jared W. (2025). Beneficial and adverse effects of THC on cognition in the HIV-1 transgenic rat model: Importance of exploring task- and sex-dependent outcomes.. Brain, behavior, and immunity, 128, 571-588. https://doi.org/10.1016/j.bbi.2025.04.030