Beyond the iron mask: Towards better recognition and treatment of depression associated with Parkinson's disease

Abstract

This review examines the frequency of depression complicating Parkinson's disease (PD), its aetiology and clinical features, and also how it may be recognised and treated. Studies investigating the frequency of depression in PD have yielded figures ranging between 2.7% and 70%. Methodological differences account for much of the disparity. The aetiology of depression in PD is complex, and probably relates to both biological and exogenous factors. Dysfunction of multiple neurotransmitter systems, including the serotonergic system, may be involved. Mood disturbances resulting from deep brain stimulation of the subthalamic nucleus may provide a fruitful area for future research, and assist our understanding of the neural networks involved in mediating depression. Several recent studies have confirmed that depression in the PD patient is a major determinant of quality of life and that this is closely related to dysfunction in other clinically important health areas. The validity for many existing scales in the screening, diagnosis, and monitoring of depression in the PD patient has not been established. The Montgomery-Asberg Depression Rating Scale and the Hamilton Rating Scale for Depression appear to have good diagnostic sensitivity and specificity when compared with DSM-IV criteria. Recommendations for the optimal drug treatment of depression in PD are difficult to give, due to an inexplicable dearth of sizeable, placebo-controlled studies. A majority of physicians would probably now opt for a selective serotonin reuptake inhibitor in the depressed PD patient. There is no good evidence that these drugs are associated with a worsening of motor features, but they should probably not be coprescribed with selegiline, because of the risk of causing a potentially serious serotonin syndrome. Several studies have suggested that depression in the PD patient is associated with a more rapid deterioration in cognitive and motor functions, perhaps as a surrogate marker for more extensive brainstem cell loss.

Imaging Approaches to Parkinson Disease

“…The prevalence of depression in PD has been reported to range from 10% to 45% (80). Because Lewy body pathology is known to affect serotonergic and noradrenergic as well as dopaminergic neurotransmission, dysfunction of any or all of these systems would seem to be a reasonable candidate for the functional substrate of depression (81).…”

Biomarkers for Evaluation of Clinical Efficacy of Multipotential Neuroprotective Drugs for Alzheimer's and Parkinson's Diseases

“…56 Depression in PD might be associated with a specific loss of dopamine (DA), serotonin and noradrenaline innervation in the limbic system. 57 Interestingly, several studies have suggested that depression in the PD patient is associated with a more rapid deterioration in cognitive function.…”

“…57 Interestingly, several studies have suggested that depression in the PD patient is associated with a more rapid deterioration in cognitive function. 56 Olfactory deficits reported in PD are believed to represent a sensitive marker of the disease, which could allow an early diagnosis and help in differentiating idiopathic PD from other diseases with features of Parkinsonism. The diagnostic accuracy of olfactory testing in differentiating PD from other disorders is however insufficient to justify routine clinical use.…”

Neuropsychiatric Phenomena Associated With Movement Disorders

“…In Parkinson's disease, depression is seen in nearly 50% of cases. 9 At the same time, depression is severely underrecognized by clinicians who treat patients with movement disorders, 10 quite possibly owing to the significant clinical overlap between these conditions. Symptoms common to movement disorders and depression are as follows 10,11 :…”