Motor dysfunction in schizotypal personality disorder.

Past research has revealed that schizophrenia is associated with voluntary movement abnormalities, as well as higher rates of involuntary movements. On instrumental motor tasks, patients manifest reduced motor stability, excessive force and more contralateral motor overflow (movement in the non-responding hand). In the present study, an instrumental motor task (manual response forced-choice task) was administered to a group of adults with schizotypal personality disorder (SPD) in order to determine whether they show motor deficits similar to those observed in schizophrenia. As predicted, the schizotypal subjects were excessive and more variable in motor force, compared to healthy controls and other personality-disordered subjects. Additionally, the force and variability of the motor responses were positively correlated with ratings of both positive and negative SPD symptoms. Finally, motor overflow and negative symptoms were associated with higher salivary cortisol levels. The pattern of findings is consistent with previous reports linking motor abnormalities and heightened cortisol with schizotypal personality disorder.