HALOPERIDOL ENHANCES LATENT INHIBITION IN VISUAL TASKS IN HEALTHY PEOPLE

We have previously shown that 0.5 mg haloperidol (IV) increased latent inhibition in one of two visual tasks, The present study analysed the effects of a higher dose of haloperidol (1.0 mg, IV) on latest inhibi tion in these two visual tasks in healthy volunteers in a randomised c ontrolled trial. In the task where 0.5 mg haloperidol had enhanced lat ent inhibition, 1.0 mg had the same effect, thus replicating the previ ous result, In the task where 0.5 mg haloperidol had been ineffective, 1.0 mg haloperidol enhanced latent inhibition in high schizotypal sub jects only. This indicates that subjects with higher schizotypy scores are more sensitive to dopamine blockade. A comparison of the results from the studies at the two different doses suggests a dose dependence of haloperidol's effects on latent inhibition that parallels results from animal work.