Depression Common But Often Untreated in Early Parkinson's Disease

Marlene Busko
July 17, 2007 — In a study of more than 400 patients with early Parkinson's disease enrolled in 2 phase 2 clinical trials, depression was common, often untreated, and linked with impairments in activities of daily living.
The study, led by Bernard Ravina, MD, from the University of Rochester School of Medicine, in New York, was published online June 20 and will be in the July 24 issue of Neurology.
Study author Richard Camicioli, MD, from the University of Alberta, in Edmonton, told Medscape: "[First,] this suggests that depressive symptoms are present at the earliest stage of Parkinson's disease. The second point is that people followed in a clinical-trials setting, in centers that manage this disease, were often not started on antidepressants or referred for psychiatric evaluation, despite the presence of depressive symptoms." This suggests that in the general-practice setting too, there is a need for greater awareness of depression in early Parkinson's disease and a need to consider appropriate treatment and referral for these patients, he added. "We typically think of Parkinson's disease as a movement disorder, but [these patients] also have nonmovement symptoms that are really important."
The group writes that previous studies determined that depression affects up to 50% of patients with Parkinson's disease, but symptoms of depression, such as insomnia and fatigue, are often mistakenly attributed to Parkinson's disease itself. The group aimed to examine the impact of depressive symptoms in early, untreated Parkinson's disease.
They performed a secondary analysis of 2 phase 2 multicenter clinical trials of patients diagnosed with Parkinson's disease within the previous 5 years. Funded by the National Institutes of Health, these were futility trials designed to evaluate whether potential neuroprotective agents should be studied further. The first trial, FS1, randomized 200 patients to creatine, minocycline, or placebo, and the second trial, FS-TOO, randomized 213 patients to coenzyme Q, GPI-1485, or placebo.
The team investigated the relationship between depression, motor function, and activities of daily living and depression treatment decisions. The 15-item Geriatric Depression Scale (GDS-15) was used to assess depression: a score of 5 to 9 was defined as mild depression and a score of more than 9 was defined as moderate to severe depression. Motor function and activities of daily living were assessed using the Unified Parkinson's Disease Rating Scale.
Depression Common, Mostly Mild Symptoms
During the average 14.6 months of follow-up, 114 of the 413 study subjects (27.6%) experienced depression. Of these 114 subjects, 28 (25%) had persistent symptoms despite receiving treatment and 40 (35%) were started on antidepressants or referred to a psychiatrist, but 46 (40%) did not receive treatment for depression.
A total of 57 subjects who were not depressed at baseline developed depression during follow-up. Most subjects with moderate to severe incident depression (4 of 5 subjects) received treatment, but fewer subjects with incident mild depression (only 8 of 52) received treatment.
This suggests that depression in Parkinson's disease is mostly minor depression and possibly may go untreated because it is not thought to require treatment, the group writes. They add that evidence suggests that the detection and treatment of mild depressive symptoms in Parkinson's disease might improve outcomes.
Depression Linked with Disability, Greater Awareness Needed
Depressive symptoms contributed to clinically important impairments. A GDS-15 score of 5 or greater (indicating depression) was significantly associated with more impaired activities of daily living (P < .0001) and with a clinical determination of the need to start symptomatic therapy for Parkinson's disease (adjusted hazard ratio, 1.83; 95% CI 1.27 – 2.63; P = .001). "Depressive symptoms are an important contributor to disability and the decision to start symptomatic therapy for motor-related impairment in early Parkinson's disease, highlighting the broad importance of identifying and treating depression in this population," the group concludes. Patients and physicians are quite aware of the slowing of movement, the tremor, and all the motor symptoms that are really prominent in Parkinson's disease, but "mood is also a part of that and also impacts how patients do," said Dr. Camicioli. Neurology. 2007. Published online June 20, 2007.