A retrospective analysis of the U.S. National Parkinson’s Foundation (NPF) database has found that clinical recognition of depression in Parkinson’s disease has improved but almost one-half of patients remain untreated (Bega et al. J Parkinsons Dis 2014; epublished July 17, 2014; free full text at http://iospress.metapress.com/content/92617284j0410402/fulltext.pdf). The study was part of the NPF’s Quality Improvement Initiative.

The analysis included data for 7,031 patients collected prospectively from movement disorder centres in North America; average age was 58 years and mean duration of illness was 8.9 years. The emotional domain of the Parkinson’s Disease Questionnaire (PDQ-39) was used as a measure of depressive symptoms rather than a depression inventory.

Overall, 23% of patients had clinically significant symptoms of depression (PDQ-39e >10). One-third were taking antidepressants, 6% were using mental health services and 14% were using both; 47% remained untreated. Patients with untreated depression tended to be older, with a shorter duration of PD, living at home, and with a spouse/partner as the regular care partner. During the one-year observation period, 9.3% of patients with depression started treatment for depression (antidepressants or counselling).

The authors noted that while a majority of PD patients with depressive symptoms were receiving treatment, data were obtained from PD centres of excellence, and detection of depression by clinicians in the community may be lower. A further observation was that many patients with treated depression continued to have symptoms of depression, which may indicate either that more severe depression is more likely to be treated or that current therapies are only partially effective.

Comment
Dr. Susan Fox: This large multicentre study shows that depression is common in PD. The importance of this report is that the evidence was gathered from patients and caregivers, not physicians, and shows a disconnect between the two. Physicians need to ask about depression at every visit. Treating PD depression can be challenging due to concerns about side effects of antidepressants, interactions with other drugs and an often poor response to antidepressants. Other approaches may be needed, including use of dopaminergic agents, encouraging non-pharmacological approaches (e.g. exercise), in particular, making use of psychiatry colleagues for challenging cases.