A cup of coffee may help control symptoms of patients with Parkinson's disease, a new study revealed.

Researchers found that while caffeine intake does not seem to improve sleepiness among people with Parkinson's disease, it appeared to help control movement in patients with the disease.

While previous studies have shown that people who use caffeine are less likely to develop Parkinson's disease, the latest study is the first to show that caffeine can help with movement symptoms for patients who already have the disease, according to lead author Dr. Ronald Postuma of McGill University in Montreal and the Research Institute of the McGill University Health Center.

The study consisted of 61 patients with Parkinson's disease who showed symptoms of daytime sleepiness and some motor symptoms. Participants were given either placebo pills throughout the study or a tablet with 100 milligrams of caffeine two times a day for three weeks, then 200 milligrams twice a day for three weeks, equivalent to about two to four cups of coffee a day.

Researchers found that after six weeks, half of the participants who were taking the caffeine supplements improved on average by about five points in Parkinson's severity ratings compared to those who didn't consume caffeine.

"This is a modest improvement, but may be enough to provide benefit to patients. On the other hand, it may not be sufficient to explain the relationship between caffeine non-use and Parkinson's, since studies of the progression of Parkinson's symptoms early in the disease suggest that a five-point reduction would delay diagnosis by only six months," Postuma said in a statement.

Participants taking the caffeine also improved on average by three points in the speed of movement and the amount of stiffness compared to the placebo group.

However, researchers noted that caffeine did not appear to improve daytime sleepiness or quality of life, depression or sleep quality in Parkinson's patients.

"The study is especially interesting since caffeine seems to block a malfunctioning brain signal in Parkinson's disease and is so safe and inexpensive," Dr. Michael Schwarzschild of Massachusetts General Hospital in Boston, who wrote an accompanying editorial, said in a news release.

"Although the results do not suggest that caffeine should be used as a treatment in Parkinson's disease, they can be taken into consideration when people with Parkinson's are discussing their caffeine use with their neurologist." Schwarzschild added.

The researchers noted that the length of time in the study was short, and that the beneficial effects of caffeine may lessen over time.

The study was published in Neurology.