Certain antidepressants appear to decrease depression in people with Parkinson disease without worsening motor problems, according to a study published in the April 11, 2012, online issue of Neurology®, the medical journal of the American Academy of Neurology.
"These results are exciting because depression is common in Parkinson's but we weren't sure about the best way to treat it. Older antidepressants are effective but have a lot of side effects. The newer antidepressants have fewer side effects but we didn't know if they'd be effective in people with Parkinson's. We were also worried that they might worsen the motor problems that come with the disease," said research author Irene H Richard MD, of the University of Rochester Medical Center in New York and a member of the American Academy of Neurology.
Almost one half of people with Parkinson disease suffer from depression, and it is a major cause of disability.
The drugs tested were paroxetine, which is an antidepressant in the selective serotonin reuptake inhibitors (SSRIs) class, and venlafaxine extended release, which is in the serotonin and norepinephrine reuptake inhibitors (SNRIs) class.
The clinical trial lasted 3 months and involved 115 people in various stages of Parkinson disease who met the criteria for depression. About one third of the participants received paroxetine, one third received venlafaxine, and one third received a placebo. The dosage of the drug could be increased until the participant's depression was effectively treated.
On average, the people receiving paroxetine had a 13 point (59%) improvement and those receiving venlafaxine had an 11 point (52%) improvement in their scores on the Hamilton Rating Scale for Depression. People who receivedplacebo had a 6.8 point (32%) improvement. The results, as measured by 3 other depression rating scales, were similar. "The study suggests that, while there is a clear 'placebo' effect, there is a greater benefit from the antidepressant medications," said Richard.
The drugs were generally well tolerated and did not lead to any worsening in motor functioning.
The study was supported by the National Institutes of Health/National Institute of Neurological Disorders and Stroke and Johns Hopkins University School of Medicine. Wyeth Pharmaceuticals provided venlafaxine XR, and Glaxo-Smith Kline provided paroxetine.
Source: News Release
American Academy of Neurology
April 11, 2012