Motor deficits and schizophrenia: the evidence from neuroleptic-naïve patients and populations at risk

Patients with schizophrenia and high-risk populations have elevated rates of eye movement abnormalities. However, it is not known whether these abnormalities are specific to eye movements or whether they are also found in more traditional domains of motor control. Most studies examining the motor function of patients with schizophrenia have involved patients treated with medication; abnormalities in motor function could be a result of treatment rather than the disease itself. If motor abnormalities are related to schizophrenia, they should also be found in neuroleptic-naïve patients and possibly in high-risk populations in whom eye movement abnormalities are also observed. We reviewed relevant empirical papers published in the last 35 years. Results suggest that approximately one-fifth of neuroleptic-naïve patients with schizophrenia have increased rates of parkinsonism and neurological soft signs. In high-risk populations, replicated findings include delayed motor development in preschizophrenia subjects, and poor motor skills in the offspring of patients with schizophrenia. In first-degree relatives, increased rates of neurological soft signs were reported. These findings suggest that motor abnormalities are not limited to eye movements and may constitute markers of vulnerability. The literature has several weaknesses that should be addressed in future studies.