Context: Because recent findings suggest that early treatment may ameliorate the course or even prevent the onset of schizophrenia and other psychotic disorders, longitudinal high-risk research on biological markers of risk has become a priority. Within this context, premorbid movement abnormalities are of particular interest because the neurocircuitry hypothesized to give rise to dyskinetic movements has also been implicated in psychotic symptoms. To date, there have been no published longitudinal studies examining the progression of movement abnormalities and their relation with symptom progression in at-risk youth.
Objective: To examine the progression of movement abnormalities in relation to positive and negative symptoms in adolescents at high risk of developing psychotic disorders.
Design: Naturalistic, prospective, longitudinal design.
Setting: Participants recruited through announcements directed at parents of adolescents showing schizotypal symptoms.
Participants: One hundred twenty-one adolescents (mean baseline age, 14.26 years), 32 with schizotypal personality disorder, 49 nonclinical controls, and 40 with other personality disorders.
Main outcome measures: Participating adolescents were evaluated for personality disorders (Structured Interview for DSM-IV Personality Disorders), prodromal symptoms (Structured Interview for Prodromal Symptoms), and movement abnormalities (Dyskinesia Identification System Condensed User Scale) at 3 annual assessments.
Results: The schizotypal group exhibited significantly elevated movement abnormalities in comparison with controls across all 3 time points. Further, the schizotypal personality disorder group alone showed significant increases in movement abnormalities over time. Movement abnormalities were correlated with prodromal symptoms at each time period, and for several body regions, the magnitude of this relationship significantly increased over time.
Conclusions: The results are consistent with the hypothesis of shared neural circuitry for movement abnormalities and psychotic symptoms and suggest the potential value of including an assessment of motor signs in screening for psychosis risk.