Mood Drug Lithium Shows Promise Fighting Hidden HIV

A drug that's been helping people manage mood disorders for decades might become an unexpected weapon in the fight against HIV.

Researchers at McGill University published findings in iScience showing that lithium can prevent dormant HIV from reactivating inside infected cells. The discovery opens new doors for developing a functional cure, one that could keep the virus asleep indefinitely without eliminating it entirely.

About 40.8 million people worldwide lived with HIV in 2024. While daily antiretroviral therapy keeps the virus under control, it remains hidden in immune cells, ready to rebound if treatment stops. A functional cure would keep HIV dormant, potentially freeing patients from lifelong daily medication.

"One major thrust in HIV cure research is asking whether existing drugs can be repurposed," said Andrew Mouland, Professor in McGill's Department of Medicine. Because lithium is already approved and inexpensive, it offers a faster starting point than creating new drugs from scratch.

The research team, led by Ana-Luiza Abdalla during her Ph.D. studies, directly suppressed HIV reactivation in lab-grown human cells. That clear demonstration hadn't been achieved before with lithium.

The bigger surprise came when they uncovered how it works. Scientists had long assumed lithium kept HIV dormant by activating autophagy, the cell's natural recycling system. Using a special fluorescence test that distinguishes between sleeping and active virus, the team disrupted autophagy and watched lithium keep working anyway.

"What surprised us was that the effect persisted even when we disrupted autophagy," Abdalla said. That means other biological pathways are involved, possibly ones the virus relies on to restart itself.

The Bright Side: This research represents exactly the kind of creative thinking that accelerates medical progress. Instead of starting from zero with experimental compounds, scientists are looking at medications already proven safe for human use. That speeds up the path from laboratory to potential treatment.

The findings also reveal new biological mechanisms that future HIV therapies could target. Researchers can now design treatments that mimic lithium's beneficial effects while avoiding its side effects, which can be significant for some patients.

Mouland emphasized that people with HIV shouldn't take lithium based on this research. The psychoactive drug hasn't been tested in humans as an HIV treatment and carries risks. But the discovery gives researchers a proven biological pathway to explore and refine.

For millions living with HIV worldwide, this study adds another piece to the cure puzzle. Each insight brings science closer to the day when HIV becomes a manageable condition requiring minimal intervention, transforming lives in the process.