A Narrative Review of the Psychiatric Aspects of Deep-Brain Stimulation for Movement Disorders: A Role for Consultation-Liaison Psychiatrists

Deep brain stimulation (DBS) is a neuromodulatory intervention primarily utilized in treatment-refractory motor symptoms of Parkinson disease (PD), dystonia, and essential tremor. Primary DBS target sites for treatment of movement disorders include subcortical regions with important connections to the limbic, associative, and motor systems, potentially leading to neuropsychiatric symptoms.

We sought to highlight the role that consultation-liaison psychiatrists can play in multidisciplinary care for patients with movement disorders by reviewing the literature on psychiatric disorders and clinically significant psychiatric symptoms before and after DBS.

This narrative review was conducted utilizing a literature search using PubMed and Google Scholar. The review focused on (1) the prevalence of psychiatric disorders and/or clinically significant psychiatric symptoms in treatment-refractory PD, dystonia and essential tremor, and the impact of these symptoms on quality of life and functioning and (2) the incidence and/or prevalence of, and risk factors for, psychiatric disorders and/or clinically significant psychiatric symptoms after DBS for these movement disorders.

Over two-thirds of patients with PD will experience clinically significant psychiatric symptoms over the course of the disease. Over 90% of patients with dystonia may develop a psychiatric disorder over their lifetime. Nearly three-quarters of patients with essential tremor will experience clinically significant psychiatric symptoms. Psychiatric symptoms have been associated with negative impacts on quality of life and functioning across all 3 movement disorders. Up to three-fifths of patients undergoing DBS for treatment refractory movement disorders may experience clinically significant psychiatric symptoms within weeks of surgery. Suicides have been reported following DBS for PD and dystonia. Potential risk factors for post-DBS clinically significant neuropsychiatric symptoms in patients with PD include advanced age, pre-DBS cognitive impairment and psychiatric disorders, and stimulation of ventral nonmotor subcortical brain regions.

Psychiatric disorders and clinically significant psychiatric symptoms are common in patients with PD, dystonia or essential tremor before DBS therapy. Clinically significant neuropsychiatric symptoms, including completed suicides, are prevalent following DBS for PD or dystonia. Consultation-liaison psychiatrists can play a vital role in the multidisciplinary care of patients with treatment-resistant movement disorders undergoing DBS through routine psychiatric screening, evaluation and follow-up.