Stereotypies in adults: a systematic review

Stereotypies are abnormal involuntary non-goal-directed movement patterns or vocalisations which repeat continuously in the same fashion over a period of time and on multiple occasions and are typically distractible. Stereotypies are common in both children and adults, but they are extensively reviewed only in children. There are very few studies, mainly in the form of case reports and case series, focusing on stereotypies occurring in adults as part of different neurological disorders. In adults, stereotypies can be both physiological and pathological. Common physiological stereotypies in adults are leg shaking, face touching, playing with pens or hair, nail biting, hand tapping, foot tapping, and body rocking. Pathological stereotypies in adults are associated with a variety of neuropsychiatric conditions like neurodegenerative disorders, viral encephalitis, autoimmune encephalitis, stroke, psychiatric illness, and drug use. In this review, we focus on the various causes of stereotypic movements in adults, and their pathophysiology, clinical manifestations, and treatment.