Psychiatric Issues in Parkinson’s Disease: A Practical Guide

Psychiatrists are well aware of the parkinsonian side effects and tardive dyskinesias that are induced by neuroleptics. We are, unfortunately, often considerably less knowledgeable about the important and disabling psychic and behavioral aspects of Parkinson"s disease and its treatments. These problems will be seen in ever greater numbers in our rapidly aging population. It has been estimated that 1% of people over the age of 50 and perhaps 2.5% of those over 70 suffer from Parkinson"s disease, and many of them have additional complicating problems such as parkinsonian side effects and tardive dyskinesia. These patients require ongoing, long-term care and management. We all need to educate ourselves to better help patients deal with the problems of Parkinson’s disease, which is a chronic and progressive neurodegenerative disorder. In Psychiatric Issues in Parkinson’s Disease: A Practical Guide, Matthew Menza and Laura Marsh offer us a good (but not great) introductory text on this important topic.

The book is divided into four sections that present the neurology of Parkinson"s disease, the accompanying cognitive dysfunctions, the common psychiatric disturbances, and a group of special topics, including disability, personality issues, and rehabilitation. The language throughout is simple and straightforward; the references for each chapter are extensive and up-to-date (including many articles published in 2004); and the index is comprehensive and useful. An appendix tabulates the drug treatments used for psychosis, depression, and insomnia, with helpful comments about side effects and complications. A second appendix lists the various websites and organizations available for patients and their families. One minor caveat is that there is an overuse of initials as abbreviations (e.g. EDS for excessive daytime sleepiness, DRT for dopaminergic replacement therapy, and PLMS for periodic leg movements of sleep). While abbreviations shorten the text, it is always more difficult for the reader when nonstandard abbreviations are used.

As noted in one of the book’s chapters, Parkinson’s disease is properly classified as a neuropsychiatric disorder rather than a neurological illness. Its presenting symptoms almost always include prominent behavioral and psychiatric features. It is also an example of the need to employ George Engel’s biopsychosocial approach. All patients with Parkinson’s disease show some cognitive changes, although these changes do not usually become prominent until the disease has progressed, with dementia being rare until the late stages (8–10 years after clinical onset). Depression is present in both early and late stages and is seen in 20%-40% of patients, although some estimates are as high as 75%. Accurate diagnosis is made difficult by the confounding and overlapping nature of the typical symptoms, which include loss of motility, facial mimesis, and apathy. Reactive states are perhaps more common in the early stages when patients begin to be aware of the disease’s impact on their lives, and biological depression is more common in later stages, perhaps as a direct effect of the ongoing neurodegenerative processes. Anxiety is also common in patients with Parkinson’s disease, and psychosis may occur in as many as 50% of patients, often as a complication of dopaminergic replacement treatment or from the increasing cognitive distortions of later stages of the disease.

Treatment of these comorbid conditions, whether they are reactive or inherent in the disease, is complicated by the fact that 1) most of the current medications interact poorly with the underlying pathologies and 2) all patients are unique in both the clustering of their symptoms and in their responses to medication and other therapeutic interventions. The authors encourage individualized treatment plans. They are also cautious in their recommendations regarding medication; they encourage the use of a variety of both psycho- and physiotherapies; and they are properly attentive to the needs of family and other caregivers. There are many sensible suggestions regarding management throughout the book. However, the authors repeatedly note the unfortunate absence of controlled studies and look forward to the availability of the rapidly advancing knowledge in the field. When this additional information becomes available, these same authors will be able to provide us with a great text.