Anxiety is common in Parkinson's disease (PD), and contributes to increased disability and poorer quality of life. In spite of its significant impact, the symptomatology, chronology, and neurobiology of anxiety in PD are all poorly understood, and this hinders accurate diagnosis and development of effective treatment strategies. This review investigates and updates literature related to the clinical spectrum of anxiety in PD. The reported prevalence of anxiety in PD varies considerably, with emerging interest in the frequency of the DSM-IV residual category of "Anxiety disorder, not otherwise specified" (Anxiety disorder NOS), which is observed in up to 25% of PD patients. By design, there are no standardized diagnostic criteria for Anxiety disorder NOS, because this is the category applied to individuals who do not meet diagnostic criteria for any other current anxiety disorder. Anxiety rating scales incompletely capture anxiety symptoms that relate specifically to PD symptoms and the complications arising from PD therapy. Consequently, these scales have been deemed inappropriate for use in PD, and there remains a need for the development of a new PD-specific anxiety scale. Research establishing accurate symptom profiles of anxiety in PD is sparse, although characterizing such symptomatology would likely improve clinical diagnosis and facilitate targeted treatment strategies. Research into the neurobiological and psychological underpinnings of anxiety in PD remains inconclusive. Anxiety can precede the onset of PD motor symptoms or can develop after a diagnosis of PD. Further investigations focused on the chronology of anxiety and its relationship to PD diagnosis are required.

Careful characterization of PD-specific anxiety symptomatology provides a basis for conceptualizing anxiety and assists with the development of a new PD-specific measure to accurately assess anxiety in PD.

Background: Anxiety disorders are common in Parkinson's disease (PD) and are undertreated. The current study investigates demographic and PD-specific factors associated with Diagnostic and Statistical Manual (DSM-IV) anxiety disorders and subsyndromal anxiety in PD. It also examines the use of pharmacological and nonpharmacological treatments for anxiety in PD. Methods: Ninety nondemented PD patients completed a semistructured interview. Logistic regression models were constructed examining associations between several demographic, disease-specific, and treatment factors, as well as both current syndromal, DSM-IV anxiety disorders, and subsyndromal anxiety. Results: Associations were found between current DSM-IV anxiety disorder, as well as female gender, younger age, more severe stages of PD, and poor activities of daily living. Subsyndromal anxiety was related to a younger onset age of PD. Relationships were also found between both anxiety groups and more complications of PD therapy, as well as higher depression scores. There were no associations between anxiety and levodopa equivalent daily dosage, motor disability, and cognition. In our sample, 57% of patients with current DSM-IV anxiety disorders or subsyndromal anxiety were not currently treated with pharmacotherapy. Of those who currently received such treatment, 83% still experienced current anxiety disorders. Results suggest that anxiety is poorly recognized and treated in PD. Conclusions: Clinical trials investigating the efficacy of pharmacotherapy, tailored psychotherapy, and combination therapy primarily focusing on anxiety are much needed, with the aim of establishing novel targeted treatment protocols for the management of subtypes of anxiety disorders in PD.