Motor behavior abnormalities in drug-naïve patients with schizophrenia spectrum disorders

Abstract

Prevalence and correlates of primary motor abnormalities in schizophrenia are presently ill defined. This study was aimed at examining the prevalence, syndromic structure, external correlates, and response to antipsychotic medication of a broad array of primary motor abnormalities. Two-hundred antipsychotic-naive patients with schizophrenia spectrum disorders were examined for motor abnormalities using the Modified Rogers Scale. Thirty-one motor signs were subjected to factor analysis, and the resulting factors examined for association with a number of risk factors, clinical and psychopathological variables. One-hundred and eighty-nine patients were reassessed for motor abnormalities after completing a 4-week trial with antipsychotic medication. Prevalence rates for at least one motor sign and syndrome at baseline were 66% and 40%, respectively. Motor signs clustered together into seven clinically interpretable factors: abnormal involuntary movements, hypokinesia, retarded catatonia, echo-phenomena, excited catatonia, catalepsy, and parkinsonism. All motor domains but parkinsonism were inter-related. Abnormal involuntary movements were associated with variables indicating both neurodevelopmental dysfunction and illness severity, and most motor domains were closely related to negative or disorganization symptoms. Change scores in motor domains after treatment with antipsychotic medication indicated improvement for abnormal involuntary movements, hypokinesia, retarded catatonia, excited catatonia and echophenomena, and worsening for parkinsonism. It is concluded that primary motor dysfunction is a prevalent and heterogeneous condition of schizophrenia. Motor abnormalities segregate into various syndromes, which have different clinical correlates and a differential response pattern to antipsychotic medication. It is hypothesized that the existence of a differential dopaminergic dysfunction in the nigroestriatal circuitry is responsible for the generation of those motor domains that improve and worsen with antipsychotic drugs.