Anxiety disorders are common in Parkinson's Disease (PD), but are not well-characterized. This study determined the prevalence and clinical correlates of all DSM-IV-TR anxiety disorder diagnoses in a sample of 127 subjects with idiopathic PD who underwent comprehensive assessments administered by a psychiatrist and neurologist. A panel of six psychiatrists with expertise in geriatric psychiatry and/or movement disorders established by consensus all psychiatric diagnoses. Current and lifetime prevalence of at least one anxiety disorder diagnosis was 43% (n=55) and 49% (n=63), respectively. Anxiety Disorder Not Otherwise Specified, a DSM diagnosis used for anxiety disturbances not meeting criteria for defined subtypes, was the most common diagnosis (30% lifetime prevalence, n=38). Compared to non-anxious subjects, panic disorder (n=13) was associated with earlier age of PD onset [50.3(12.2) vs. 61.0(13.7) years, p<.01], higher rates of motor fluctuations [77% (10/13) vs. 39% (25/64), p=.01] and morning dystonia [38% (5/13) vs. 13% (8/62), p<.03]. This high prevalence of anxiety disorders, including disturbances often not meeting conventional diagnostic criteria, suggests that anxiety in PD is likely under-diagnosed and under-treated and refined characterization of anxiety disorders in PD is needed. In addition, certain anxiety subtypes may be clinically useful markers associated with disease impact in PD.

Donepezil has a beneficial effect on memory and may improve other cognitive deficits in patients with PD and cognitive impairment. However, variable tolerability in our sample underscores the need for careful monitoring when prescribing donepezil to patients with PD, especially with dosage increases.

Nonpsychotic psychiatric disturbances, especially affective disturbances, are common comorbidities in PD patients with psychosis and warrant clinical attention to reduce morbidity and caregiver distress.