Depression in Parkinson’s disease

Depression is highly prevalent in PD; 35% of patients with PD report clinically significant depressive symptoms, and 17% have major depressive disorder.^2,3 The symptoms of depression may often go unrecognised and, thus, untreated.⁶ The reduced facial expression (hypomimia) and general slowness of movement associated with bradykinesia may mask certain aspects of depression, complicating the diagnosis.⁷ Depression is a key determinant of reduced quality of life in patients with PD.¹ It is associated with sleep disturbances, fatigue, decreased functional ability, and reduced ability to perform activities of daily living.¹

The underlying cause of PD-related depression can be difficult to identify.¹ In some cases, it may be a reactive state in which an individual struggles with their condition.¹ Depression may also occur as an intrinsic part of the neurodegenerative pathology of PD (perhaps explaining the high risk of depression prior to the onset of clinical motor symptoms).^1,8

Treatment of depression in PD is broadly similar to treatment of depression in people without PD.^1,6 This comprises a mixture of pharmacological therapies,¹ and non-pharmacological therapies (e.g., patient support groups,¹ cognitive behavioural therapy,¹ mindfulness training,⁹ and exercise).¹⁰ Patients may also benefit from adjusting their dopaminergic medication, since depressive symptoms can be worse during periods of dopamine deficiency (‘OFF’ periods).⁶

References:
1. Tan LC. Mood disorders in Parkinson’s disease. Parkinsonism Relat Disord 2012; 18 (Suppl 1): S74–S76.

2. Reijnders JS, Ehrt U, Weber WE, et al. A systematic review of prevalence studies of depression in Parkinson’s disease. Mov Disord 2008; 23 (2): 183–189.

3. Schrag A. Quality of life and depression in Parkinson’s disease. J Neurol Sci 2006; 248 (1–2): 151–157.

4. Schrag A, Bohlken J, Dammertz L, et al. Widening the spectrum of risk factors, comorbidities, and prodromal features of Parkinson disease. JAMA Neurol 2023; 80 (2): 161–171.

5. Aarsland D, Påhlhagen S, Ballard CG, et al. Depression in Parkinson disease – epidemiology, mechanisms and management. Nat Rev Neurol 2011; 8 (1): 35–47.

6. Connolly B, Fox SH. Treatment of cognitive, psychiatric, and affective disorders associated with Parkinson’s disease. Neurotherapeutics 2014; 11 (1): 78–91.

7. Weiss HD, Pontone GM. “Pseudo-syndromes” associated with Parkinson disease, dementia, apathy, anxiety, and depression. Neurol Clin Pract 2019; 9 (4): 354–359.

8. Schrag A, Horsfall L, Walters K, et al. Prediagnostic presentations of Parkinson’s disease in primary care: a case-control study. Lancet Neurol 2015; 14 (1): 57–64.

9. Dissanayaka NNW, Jion FI, Pachana NA, et al. Mindfulness for motor and nonmotor dysfunctions in Parkinson’s disease. Parkinsons Dis 2016; 2016: 7109052.

10. Reynolds GO, Otto MW, Ellis TD, et al. The therapeutic potential of exercise to improve mood, cognition, and sleep in Parkinson’s disease. Mov Disord 2016; 31 (1): 23–38.