The study – published in Neurology – investigated the effects of caffeine on Parkinson disease symptoms, noting that whilst epidemiologic studies have ‘consistently’ linked caffeine consumption to a lower risk of the disease, research into the symptomatic effects of caffeine in Parkinson’s “have not been adequately evaluated.”
"This is one of the first studies to show the benefits of caffeine on motor impairment in people who have Parkinson's disease," said Dr Ronald Postuma, lead author of the study.
"Research has already shown that people who drink coffee have a lower risk of developing Parkinson's disease, but until now no study had looked at the immediate clinical implications of this finding," said the lead researcher, who is based at McGill University, Canada.
“This is one of the first studies in humans to show that caffeine can help with movement symptoms for people who already have the disease."
Postuma noted that the results of the study open the door to potential new therapies for the symptoms of Parkinson’s.
Caffeine is the most widely used stimulant in the world. The compound acts on the central nervous system and cardiovascular system by temporarily decreasing tiredness and increasing alertness.
Postuma noted that sleepiness is commonly associated with Parkinson's disease: "We wanted to discover how caffeine could impact sleepiness as well as the motor symptoms of Parkinson's disease, such as slowness of movement, muscle stiffness, shaking and loss of balance."
The researchers followed a group of 61 people with Parkinson's. While the control group received a placebo pill, the other group received a 100 mg dose of caffeine twice a day for three weeks and then 200 mg twice a day for another three weeks – the equivalent of between two and four cups of coffee per day.
"The people who received caffeine supplements experienced an improvement in their motor symptoms over those who received the placebo," said Postuma, who added that the team found a five-point improvement on the Unified Parkinson's Disease Rating Scale (a rating scale used to measure the severity of the disease).
"This was due to improvement in speed of movement and a reduction in stiffness," he explained.
Postuma added that whilst the five-point improvement was ‘modest’, it may be enough to provide benefit to people with Parkinson’s.
Caffeine did not appear to help improve daytime sleepiness and there were no changes in quality of life, depression or sleep quality in study participants, said the researchers.
They added that larger-scale studies now need to be carried out over a longer time period to clarify any caffeine-related improvements in symptoms.
"Caffeine should be explored as a treatment option for Parkinson's disease. It may be useful as a supplement to medication and could therefore help reduce patient dosages," said Postuma.
Published online ahead of print, doi: 10.1212/WNL.0b013e318263570d
“Caffeine for treatment of Parkinson disease: A randomized controlled trial”
Authors: Ronald B. Postuma, Anthony E. Lang, Renato P. Munhoz, Katia Charland, Amelie Pelletier, Mariana Moscovich, et al