Today's anti-depressant medications can ease depression in Parkinson's patients without worsening other symptoms of the disease, according to a study published online in Neurology, the medical journal of the American Academy of Neurology.
"Depression is the number-one factor negatively affecting the quality of life for people with Parkinson's disease," said Irene Hegeman Richard, M.D., who led the study. "It causes a great deal of suffering among patients. The great news here is that it's treatable. And when the depression is treated adequately, many of the other symptoms become much more manageable for patients," added Richard, a neurologist at the University of Rochester Medical Center.
The findings are good news for patients with Parkinson's disease, a chronic neurologic disorder best known for causing slow movement, stiffness, balance problems and other motor difficulties. However, about half of Parkinson's patients also struggle with depression.
"It's very important to note that these patients are not depressed simply because they are dealing with a chronic neurological condition," said Richard. "Rather, the depression is caused by the underlying disease process, which also causes problems with movement and balance."
While older medications known as tricyclics help treat depression in such patients, those drugs have hefty side effects. That led physicians to try newer medications in Parkinson's patients. But recent smaller studies with these medications had mixed results, leaving some physicians to question whether these drugs were actually of any benefit. In addition, there was some concern that they might worsen patient's motor symptoms.
With funding from the National Institute of Neurological Disorders and Stroke, Richard launched the Study of Antidepressants in Parkinson's Disease or SAD-PD. The effort included 115 people with Parkinson's disease at 20 sites in the United States, Canada, and Puerto Rico. All the participants had Parkinson's disease and met the criteria for depression.
About one-third of the participants received paroxetine (brand name Paxil), a selective serotonin reuptake inhibitors (SSRIs); one-third received venlafaxine extended release (brand name Effexor), a serotonin and norepinephrine reuptake inhibitor (SNRI); and one-third received a placebo.
On average, the people receiving paroxetine had a 59 percent improvement and those receiving venlafaxine had a 52 percent improvement in their scores, according to the Hamilton Rating Scale for Depression. People who received the placebo had a 32 percent improvement. Three other depression rating scales showed similar results. The drugs were generally well tolerated and did not lead to any worsening in motor functioning.
Publication of the results marks the culmination of a decade-long effort by Richard to study the problem in depth in a quest to better treat not only her patients but similar patients around the globe. She compiled preliminary data to attract funding, then pulled together a team of dozens of clinicians and researchers spanning North America to do painstaking study and analysis of an issue that has often been unrecognized among both patients and physicians.
Today, people are becoming more knowledgeable that depression is oftentimes part of the disease, said Richard, who has witnessed striking improvement in many patients after effective treatment.
"After treatment for depression, patients and their families often see a dramatic difference in how they're feeling, within a few weeks or months. They have more interest in things. They have more energy; they're sleeping better. And oftentimes there is a great sense of relief, and a huge burden has been lifted," said Richard, associate professor of Neurology and Psychiatry.
She added that sometimes it can be difficult to spot depression in patients, because some symptoms overlap with other symptoms of Parkinson's. For instance, Parkinson's patients will be less animated, their voice will be less expressive, and many will have sleep difficulties but they may not be depressed. Careful diagnosis is crucial.