Improvement in smooth pursuit eye movements after cigarette smoking in schizophrenic patients

This study examined whether schizophrenics' cigarette smoking normalized smooth pursuit eye movement abnormalities. Fifteen schizophrenic and 15 nonschizophrenic subjects abstained from their usual cigarette smoking for an average of 10 h. Their baseline performance during a constant velocity smooth pursuit task was then assessed. The subjects smoked as much as they desired in a 10-min period and then were retested immediately postsmoking, and 10 and 20 min later. Smooth pursuit gain and the percentage of total eye movement due to various saccadic subtypes were computed using infrared oculography and computerized pattern recognition software. After smoking, smooth pursuit gain increased and the percentage of total eye movements due to leading saccades decreased significantly in the schizophrenic patients. There were no changes in the gain or leading saccades of nonschizophrenic subjects after smoking. Nicotinic receptor dysfunction may be a candidate mechanism for smooth pursuit eye movement abnormalities in schizophrenia.