M. Chapman

Smooth pursuit and saccadic abnormalities in first-episode schizophrenia.

BACKGROUND Previous studies of oculomotor dysfunction in schizophrenia have tended to concentrate on abnormalities of smooth pursuit eye tracking in chronic medicated patients. We report the results of a study of smooth pursuit, reflexive and antisaccade performance in drug naive and antipsychotic treated first-episode schizophrenic patients. METHODS Smooth pursuit and saccadic eye movements were recorded in 36 first-episode schizophrenic patients and 36 controls matched for age and estimated IQ. The schizophrenic patients were divided into drug-naive (N = 17) and antipsychotic treated groups (N = 19). RESULTS Smooth pursuit velocity gain was significantly lower than controls only in the drug-naive patients. The treated patients did not differ significantly from either the controls or the untreated group. In an antisaccade paradigm both treated and drug-naive schizophrenic patients demonstrated an increased number of errors, but only drug-naive patients also demonstrated an increased latency in initiating correct antisaccades. CONCLUSIONS These impairments are unlikely to be due to a generalized deficit in oculomotor function in the schizophrenic groups, as there were no differences between the groups in saccadic metrics on a reflexive saccade task. The results show that both smooth pursuit and saccadic abnormalities are present at the onset of schizophrenia and are integral to the disorder.

Spontaneous dyskinesia in first episode schizophrenia

In the west London prospective study of first episode schizophrenia, the prevalence and nature of abnormal involuntary movements were examined in 27 patients who had never received antipsychotic drugs and 36 who had been treated with such medication. Motor disturbance was assessed with rating scales designed to cover the full range of spontaneous and drug induced movement disorder. Only one person in the drug naïve group showed evidence of parkinsonism, a finding which contrasts with recent reports suggesting that spontaneous extrapyramidal signs may not be uncommon in such patients. However, according to ratings on the modified Rogers scale, 11% of the drug naïve group exhibited orofacial dyskinesia, 4% trunk and limb dyskinesia, 7% postural abnormalities, and 4% increased muscle tone. The respective figures in the closely matched medicated group were not significantly different except for increased muscle tone, which was significantly more common (25%). The proportion of drug naïve patients fulfilling criteria for tardive dyskinesia on the abnormal involuntary movements scale ranged from 4% to 11% depending on the criterion threshold score used. These findings are in accord with the notion that abnormal involuntary movements, particularly orofacial dyskinesia, represent a neuromotor component of schizophrenia.