Effects of amphetamine on saccadic eye movements in man: possible relevance to schizophrenia?

The antisaccade task can be used to test the voluntary control of saccadic eye movements (SEMs). In many disorders with postulated hyperdopaminergic neurotransmission, there are reports of abnormalities in SEMs. To further investigate this, the role of dopamine in SEMs, performance on an antisaccade task was examined in subjects with a history of amphetamine use (a dopamine releaser and reuptake inhibitor). A prospective design was employed in a teaching hospital setting. Six subjects (five males) with a history of amphetamine use were compared to 24 normal controls. None of the subjects were using any other substances, except alcohol and nicotine, as determined by urine screening, which we believe limited the sample size. For subjects who used amphetamine before the task, the presence of amphetamine was confirmed by urinalysis. All subjects completed the antisaccade task. Both error rates and latency rates during the antisaccade task were compared between the amphetamine users and controls. The amphetamine users had significantly increased error rates and latencies. These results may suggest that increased error rates and latencies during antisaccade tasks may be due to increased dopamine transmission, which is similar to the findings in schizophrenia.