A latent class analysis of psychological disturbance in Parkinson's disease
Article first published online: 11 JAN 2013
Copyright © 2013 John Wiley & Sons, Ltd.
International Journal of Geriatric Psychiatry
Volume 28, Issue 10, pages 1054–1060, October 2013
How to Cite
Zahodne, L. B., Marsiske, M. and Bowers, D. (2013), A latent class analysis of psychological disturbance in Parkinson's disease. Int. J. Geriat. Psychiatry, 28: 1054–1060. doi: 10.1002/gps.3927
- Issue published online: 4 SEP 2013
- Article first published online: 11 JAN 2013
- Manuscript Accepted: 5 DEC 2012
- Manuscript Received: 30 JUL 2012
- National Institute on Aging. Grant Number: T32-AG020499
- Bryan W. Robinson Endowment for Neuroscience
- American Psychological Foundation
- American Psychological Association Divisions 20 and 40
- National Parkinson Foundation Center of Excellence (UF)
Psychological symptoms are common in Parkinson's disease (PD). Psychological symptoms do not respond to psychotropic medications as well in patients with PD as in patients with psychiatric illnesses who do not have PD. Evidence that PD patients can be classified into distinct psychological symptom subgroups is conflicting. This study sought to examine potential psychological heterogeneity in PD with a broader range of instruments than has been used in previous studies.
A comprehensive battery of psychological measures assessing dysphoria, apathy, anhedonia, anxiety, and negative affect was administered to 95 PD patients without global cognitive impairment. Latent class analysis was used to identify subgroups of patients based on continuous variables derived from the psychological battery. Multinomial regression was used to examine predictors of classification.
The latent class analysis identified three subgroups with incremental levels of psychopathology across most symptom domains. One exception was a greater level of affective flattening in the “psychologically healthy” group compared with the “moderate symptoms” group. Greater motor dysfunction and less education were associated with greater severity of psychological symptoms.
These results support high psychological co-morbidity in PD, which complicates the treatment of individual symptoms. In addition, emotional blunting and anhedonia may be less indicative of widespread psychological distress than anxiety, dysphoria, and cognitive aspects of apathy. Clinicians should be aware that PD patients with greater motor dysfunction and less education are at greater risk not only for depression but also for a variety of other psychological symptoms that may not be routinely assessed. Copyright © 2013 John Wiley & Sons, Ltd.