Psychomotor, cognitive, extrapyramidal, and affective functions of healthyvolunteers during treatment with an atypical (amisulpride) and a classic (haloperidol) antipsychotic

The primary objective of this study was to compare the objective and subjec tive effects of amisulpride with those of a classic antipsychotic, haloperi dol, when both were given to healthy volunteers in representative therapeut ic doses over 5 days. The secondary objective was to compare the effects of relatively low and high doses of amisulpride to confirm the suspected dual ity of its pharmacologic activity. Twenty-one subjects participated in the four-may, randomized, double-blind, crossover study with repeated daily dos es of amisulpride 50 mg, amisulpride 400 mg, haloperidol 4 mg, and placebo. Subjects were institutionalized during treatment periods and were under 24 -hour medical supervision. They underwent a series of psychomotor and cogni tive tests 1 hour before and 3 and 6 hours after dosing on days 1 and 5. Th eir extrapyramidal disturbances and drug-related feelings were assessed at the end of each replication. Psychiatric interviews and ratings of depressi on, subjective well-being, and negative symptoms occurred on day 4. Amisulp ride 50 mg had no significant effect on any parameter. Amisulpride 400 mg h ad several adverse effects on psychomotor and, although less severe, on cog nitive performance on the fifth day only. Amisulpride 400 mg produced no si gnificant extrapyramidal disturbances in the group as a whole, although it may have in some individual subjects. Also, it produced no signs of mental disturbances on clinical rating scales or during a structured psychiatric i nterview. Haloperidol ubiquitously impaired psychomotor and cognitive perfo rmance in a similar fashion after the first and the final doses. It produce d extrapyramidal disturbances in nearly every subject, the most common bein g akathisia and the most severe, in the case of one individual, being acute dystonia. Unlike amisulpride, haloperidol produced a number of mental dist urbances, the most noteworthy being negative symptoms. Amisulpride seems to be a well-tolerated drug. Its side effects should be much less troublesome to patients using the drug on a long-term basis than those of classic anti psychotics, like haloperidol.