Motor Behavior is Relevant for Understanding Mechanism, Bolstering Prediction, And Improving Treatment: A Transdiagnostic Perspective.

Abstract

Abnormal motor behavior was long considered to be of limited value to understanding psychosis. However, research of the past decades has challenged this view by demonstrating strikingly high frequencies of the various motor signs in patients with schizophrenia across the course of the disorder, including subjects at risk or unmedicated first episode patients.1–3 Motor abnormalities arise spontaneously (linked to pathophysiology) or following psychopharmacological treatment (as side effect), yet the persistence of motor abnormalities across the course of the disorders and the effect of antipsychotics on pre-existing spontaneous motor abnormalities still require further study.3–5 In addition, studies employing instrumental motor assessments or specific rating scales have emphasized the utility of motor abnormalities for screening the risk for psychosis or staging the disorder.6,7 Some of the motor phenomena are even able to predict the general outcome of psychosis.8 For example, motor coordination deficits in the first episode indicate poor outcome after 10 years.9 Critically, hypokinetic motor abnormalities are also associated with low physical activity,10 which is a key determinant of poor physical health and increased mortality.3,4 Some motor problems in psychosis extend to other domains of psychopathology, as hand gesture deficits critically impair social interaction.11,12 Even though motor abnormalities such as tardive dyskinesia or catatonia have been discussed as distinct categorical syndromes, current research efforts have emphasized a dimensional perspective with the possibility of having multiple concurrent motor abnormalities.