ABSTRACTBackgroundAnxiety 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.ObjectivesThis study aimed to identify the demographic, psychiatric, and clinical characteristics of anxiety disorder NOS in PD.MethodsA 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.ResultsThe 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.ConclusionsThese findings suggest that PD‐specific symptoms characterize anxiety in a subgroup of PD patients who do not fulfill DSM‐IV criteria for anxiety disorders.