Defining Atypical Anxiety in Parkinson's Disease

Background: Anxiety is a major complication in Parkinson's disease (PD). Many PD patients experience clinically significant anxiety not meeting Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) anxiety disorder criteria. This atypical anxiety (anxiety disorder not otherwise specified [NOS]) is often under-recognized and its diagnosis is underdeveloped. Objectives: This study aimed to identify the demographic, psychiatric, and clinical characteristics of anxiety disorder NOS in PD. Methods: A cross-sectional design studied a convenience sample of 184 PD patients without dementia recruited from neurology outpatient clinics. A semi-structured interview using DSM-IV criteria categorized PD patients into current anxiety disorder NOS (n = 28), DSM-IV anxiety disorders (n = 42) or no anxiety (n = 86) groups. Logistic regression modeling identified characteristics associated with the anxiety disorder NOS group compared to DSM-IV anxiety and no anxiety groups. Results: The anxiety disorder NOS group was associated with motor complications of PD therapy, episodic, persistent and social anxiety symptoms, depression, non-motor experiences of daily living, poor quality of life, and female sex compared to the no anxiety group. Compared to DSM-IV anxiety, those with anxiety disorder NOS demonstrated greater global cognitive impairment, more severe motor complications of PD therapy, a greater severity and functional impact of dyskinesias, and greater complexity of motor fluctuations. Persistent, episodic, and social anxiety symptoms did not significantly differ between anxiety disorder NOS and DSM-IV anxiety groups. Conclusions: These findings suggest that PD-specific symptoms characterize anxiety in a subgroup of PD patients who do not fulfill DSM-IV criteria for anxiety disorders.