Twenty-four hyperactive or unsocialized-aggressive children participated in an exploratory double-blind crossover study comparing the cognitive effects of methylphenidate hydrochloride (0.3 mg/kg), two doses (0.25 and 0.05 mg/kg) of haloperidol, and inert placebo. Each subject received each of four drug conditions, drug order being randomized by a Latin square design. At the end of each 18-day trial period, attention, immediate recognition memory, reaction times, and seat activity were tested.
While drug effects were small, methylphenidate and, to a lesser extent, the low dose of haloperidol, facilitated performance, whereas there was some suggestion that the high dose of haloperidol may have caused a slight deterioration In performance. These results are contrasted with effects on social behavior where the latter improved behavior. No differences attributable to diagnosis were found.
John S. Werry, Michael G. Aman. Methylphenidate and Haloperidol in ChildrenEffects on Attention, Memory, and Activity. Arch Gen Psychiatry. 1975;32(6):790–795. doi:10.1001/archpsyc.1975.01760240118009