A performance-enhancing drug best known for its controversial use among athletes such as Lance Armstrong, Alexei Cherepanov and Shane Mosley may also help treat symptoms of depression and bipolar disorder, according to recent findings published in the journal European Neuropsychopharmacology. The hormone, called erythropoietin, or EPO, works by pumping more blood into the brain, possibly helping to improve cognitive function in those living with mental illness, UPI reports.

EPO is naturally produced in the body, mainly by the kidneys. The hormone is vital for the production of red blood cells, which help carry oxygen to muscles, organs and tissues. When used as a drug, EPO also helps improve endurance and recovery—making it popular among professional athletes, many of whom have been implicated in various “blood-doping” scandals. (EPO is also used to help treat anemia.)

Recently, researchers at the University of Barcelona explored the effects of EPO on the brain. For the study, scientists treated 40 people living with either depression or bipolar disorder with EPO. In addition, researchers administered a placebo saline solution to 39 study volunteers once each week during an eight-week period. Next, scientists assessed participants for cognition, mood, quality of life and social skills at weeks 1 and 9 and repeated their evaluation at week 14.

Researchers found that those who were treated with EPO showed major improvements in the speed at which they processed information. This effect lasted for six weeks after treatment but wasn’t linked to any significant changes in overall quality of life or socio-occupational function.

Study authors called the results “hypothesis-generating” and noted that further research is needed to understand exactly how the hormone works in the brain. “EPO is not ready to be rolled out as a treatment just yet and may not be for everyone,” said Kamilla Miskowiak, PhD, a neuroscience expert at the University of Copenhagen and lead author of the study. Miskowiak also cautioned that EPO isn’t safe for people who have a high risk of blood clots, including smokers.

Still, with many people living with bipolar disorder searching for an effective treatment, EPO could be an exciting new therapy. Click here to learn more about other potential new treatments for bipolar disorder, depression and other psychological illnesses.