Depression in patients with Parkinson's disease.

Parkinson's disease (PD) is a disabling neurodegenerative condition commonly complicated by the existence of comorbid depression. The prevalence rates of depression in this patient group have been reported to be as high as 40%. Currently, depression in PD is undertreated; there have been few controlled clinical trials of antidepressants in this patient group. Patients with PD are usually elderly and often administered a range of medication, therefore the choice of antidepressant must be undertaken with care. Tricyclic antidepressants (TCAs) have been studied in patients with PD and comorbid depression; however, the risk of anticholinergic side-effects means that their use is largely avoided. Selective serotonin reuptake inhibitors have comparable efficacy to the TCAs and a better tolerability profile in patients with depression; they are rapidly being considered as first-line therapy for PD patients with depression. Clinical studies in this patient group are warranted. This article reviews the characteristics of comorbid depression in patients with PD and discusses the treatment options available.