BERLIN -- About half of patients with Parkinson's disease may develop anxiety over time, researchers reported here.
In a 400-patient cohort, 16% had anxiety at baseline, and 37% developed anxiety during 5 years of follow-up, , of Leiden University Medical Center in the Netherlands, and colleagues reported at the .
Female gender, more cognitive impairment, more insomnia, and more autonomic dysfunction were associated with higher anxiety scores over time, they found.
"Anxiety is a common feature in Parkinson's, that in all likelihood partly shares a common pathophysiological mechanism with depression," they wrote.
Anxiety and depression are common neuropsychiatric features in Parkinson's disease and they may affect a patient's sense of well-being. Both may also have an adverse impact over the course of the disease, Zhu and colleagues explained.
Anxiety may be episodic or stable, it may vary with severity of motor fluctuations, and situational anxiety may be related to motor deficits -- like a fear of falling due to freezing, the researchers noted.
While many earlier studies have focused on depression, less is known about risk factors for developing anxiety. Studies of anxiety in Parkinson's patients have had cross-sectional designs, and longitudinal studies with longer follow-up have been scarce, they said.
The PROPARK cohort study, which enrolled 409 patients with Parkinson's disease who were followed for 5 years, assessed a broad range of motor and nonmotor features every year.
Of those 409 patients, 67 had anxiety at baseline (16%), and of the 316 who completed long-term follow-up, 64 developed anxiety (37%), they reported.
Patients with anxiety at baseline were more often female, but they didn't differ on disease duration, age, or age at onset of Parkinson's disease. These patients were also more severely affected on several motor and nonmotor domains, the researchers said.
Depression was the strongest factor associated with higher anxiety scores, they added.
In further analyses without depression as a covariate, female gender, more cognitive impairment, more insomnia at baseline, and autonomic dysfunction (on the gastrointestinal and cardiovascular domains) were associated with higher anxiety scores over time, they reported.
Cox proportional hazards models showed that depressive symptoms, more cognitive impairment, insomnia, and autonomic dysfunction were independent predictors of future development of anxiety, they added.
Zhu and colleagues said insomnia and autonomic dysfunction could contribute to anxiety in Parkinson's disease, and that their study is the "first to confirm a relationship between cognitive dysfunction and anxiety in Parkinson's disease."
This could be explained by abnormality of noradrenergic cells in the locus coeruleus in Parkinson's patients with cognitive dysfunction, which would "further indicate that patients with cognitive dysfunction should be monitored more closely for developing anxiety symptoms," they said.
, of the National Parkinson Foundation, who wasn't involved in the study, agreed that anxiety is a prevalent symptom in Parkinson's patients.
"You often hear about depression, and, later, disease psychosis in Parkinson's -- but anxiety is often left off the list of important factors, even though it can be very disabling," Schmidt told 鶹ý. "There are lots of people who say they don't go out of the house because of their anxiety."
He noted that pimavanserin was recently approved for Parkinson's psychosis although only "about a third of patients with Parkinson's who will develop psychosis at some point in the course of their disease. But here you can see about half of people during follow-up developed anxiety. We hear from a lot of people who say anxiety is very disabling for them."
Disclosures
The authors disclosed no financial relationships with industry.
Primary Source
Movement Disorders Society
Zhu K, et al "Factors contributing to anxiety in Parkinson's disease" MDS Meeting 2016; Abstract 347.