They said the beneficial effect of selective serotonin re-uptake inhibitors (SSRIs), the class of drug that includes Prozac, is independent of the effect on depression, a common response to having a stroke, the journal The Lancet Neurology reports.
The pills boost serotonin levels and other compounds in the central nervous system which, it is thought, improves nerve growth, according to the Daily Mail.
The study investigated the use of SSRIs in stroke after mounting evidence from smaller trials that they improve motor and cognitive functions.
The team from the University Hospital of Toulouse, France, looked at 118 patients five to 10 days after a stroke. Half were given 20 mg of Prozac, while the others got a dummy pill.
Depression was significantly less common in patients on Prozac, suggesting it could prevent the condition if given early after a stroke, said lead researcher Francois Chollet.
All patients, who had moderate to severe movement problems, also received physiotherapy.
Greater improvements in motor function were found after three months in patients on Prozac, with a 50 percent increase in scores used to measure recovery.
Importantly, this gain was significant for both the upper and lower limbs, as paralysis and weakness on one side of the body are the most common disabilities left after a stroke.