Diagnosis and treatment of psychogenic parkinsonism.

Parkinson's disease (PD) is the most common movement disorder encountered in movement disorder clinics but psychogenic parkinsonism (PP) is relatively rare. Based on a study of 32 patients, coupled with a comprehensive review of the literature, the diagnosis, clinical phenomenology, epidemiology, natural history, imaging and treatment, this article provides a critical review of PP. In addition to other PD-like symptoms, patients with PP often exhibit abrupt onset, typically in response to a stressful event, followed by a fluctuating course, early disability, bilateral shaking and slowness, non-decremental slowness when performing repetitive movements, voluntary resistance against passive movement without cogwheel rigidity, distractibility, generalised and 'give-way' weakness, stuttering speech, bizarre gait and a variety of behavioural, sexual and other motor and non-motor symptoms. Levodopa related motor complications do not occur even in the setting of chronic, high dose therapy. In some cases, differentiation between PD and PP is very difficult, and in those cases the response to placebo may be helpful. A comprehensive, multidisciplinary assessment of patients with PP, when combined with insight oriented psychotherapy, physiotherapy and treatment of comorbid depression, is often helpful, although the prognosis for this group of disorders remains relatively poor.