The clinical and prognostic value of motor abnormalities in psychosis, and the importance of instrumental assessment

•Motor abnormalities should be considered as a prodrome of psychotic disorders.•Motor abnormalities can be quantified with innovative instruments, yielding sensitive, valid and reliable data and will become the new standard.•Motor symptoms have a predictive value for the development and course of psychosis and should be added to the symptomatology of psychotic disorders besides the other psychotic symptoms.•Motor abnormalities may become the first relevant non-mental sign in psychotic spectrum disorders in particular because of its objective assessment with electronic and software-based instruments.

Motor abnormalities comprise several clinical signs intrinsic to psychosis. Critically, these features are of prognostic value in individuals at-risk for psychosis, and for those in early stages of psychotic disorders. Motor abnormalities such as tremor, rigidity, and neurological soft signs often go unrecognized. Currently, advances in this area are limited by a paucity of theoretical conceptions categorizing or linking these behaviours to underlying neurobiology affected in psychosis. However, emerging technological advances have significantly improved the ability to detect and assess motor abnormalities with objective instruments in a timely and reliable manner. Further, converging evidence has laid the groundwork for theoretically and empirically derived categorization and conceptualization. This review summarizes these advances, stressing the importance of motor abnormalities for understanding vulnerability across different stages of psychosis and introducing these innovative instrumental approaches. Patients, researchers and clinicians will benefit from these new developments, as better assessment aids the development of targeted interventions to ultimately improve the care for individuals experiencing psychosis.