Must be properly diagnosed and treated to avoid serious morbidity

Psychiatric symptoms frequently coexist with idiopathic Parkinson's disease and are often underdiagnosed and poorly treated.1 Depression and anxiety are the most common psychiatric conditions that accompany Parkinson's disease. A study by Menza et al found that 12 out of 42 patients with Parkinson's disease met the criteria for an anxiety disorder according to the Diagnostic and Statistical Manual and 11 of them had a comorbid depressive disorder.2 Recent reviews show that depression is a common and potentially debilitating aspect of Parkinson's disease, affecting 40-50% of patients.3 5 While its aetiology in Parkinson's disease is unclear (biochemical changes, psychosocial factors, and situational stressors have all been implicated), it has an adverse effect on the quality of patients' lives, and doctors should ensure that it is diagnosed and properly treated.

The diagnosis is not easy because clinical symptoms of depression can overlap with or be mistaken for those of Parkinson's disease (such as …