Recognizing and Treating Neuropsychiatric Symptoms in Parkinson's Disease

Other novel agents and techniques such as omega-3 fatty acids [107] and repetitive transcranial magnetic stimulation [108] have been reported with promising early results. Cognitive behavioral therapy (CBT), which may involve stress management techniques, sleep hygiene, and caregiver support, additionally almost always provided improvement in measured outcomes, whether the trial was controlled or open label in design. In one RCT of CBT in PD of 14 weeks’ duration, there were significantly more treatment responders in the CBT group, with a number needed to treat of only 2 [109].

Anxiety

Anxiety is also common in PD, at least as common as depression considering that prevalence estimates suggest up to 50% of patients experience it [110–112]. Manifestations of anxiety may include panic attacks, generalized anxiety disorder, social anxiety, or other phobias [113]. Anxiety has an important negative impact on health-related quality of life and is often underrecognized by clinicians [114]. While reliable and valid scales to measure anxiety have been lacking in PD, a new effort has yielded the “Parkinson Anxiety Scale” though full clinimetric properties of the scale remain to be demonstrated (sensitivity to change) [115].

Anxiety that parallels the timing of motor OFF-ON cycling is important to recognize. This “subsyndromic” anxiety or anxiety disorder not otherwise specified (ie, the anxiety does not meet DSM-IV criteria) can respond to improvement in antiparkinsonian medication dosing patterns that reduce fluctuations [116,117]. Indeed, the presence of motor fluctuations is the principle marker of anxiety in many studies [118–120]. In an analogous manner, anxiety can predate PD by years and be part of the nonmotor amalgam of features heralding the disease [6,121].

Treatment

Systematic controlled trials of anxiolytic treatment for PD are lacking; therefore, SSRIs are prescribed for this purpose as in non-PD patients. Until SSRIs are demonstrated to be of benefit in anxiety, they are likely safer than use of benzodiazepines, which are associated with risk for falling, cognitive dysfunction, or autonomic dysregulation in PD patients when used during waking hours. Psychotherapy and other nonpharmacologic approaches are likely to be of benefit. A small study of neuromuscular (massage) therapy demonstrated improvement on the Beck Anxiety Inventory in PD [122]. A case report of ECT for severe anxiety has been published [123].

Conclusion

Neuropsychiatric symptoms are common in PD and new knowledge about clinical features, epidemiology, and treatment options has been gained in the last decade, though much remains to be discovered. The development of valid instruments to measure neuropsychiatric symptoms has been vital in these research efforts to bridge the gaps in our understanding. Further elucidation of the pathophysiologies of neuropsychiatric symptoms will help to define treatment targets and likely fuel drug development and the discovery of drugs with more potent benefit and fewer side effects.

Corresponding author: Kathryn A. Chung, MD, Department of Neurology, Oregon Health & Science University, Portland, OR, chungka@ohsu.edu.

Financial disclosures: None.