Reviewed were several research studies using varying dosages of methylphenidate (Ritalin) in contrast with thioridazine and amphetamine under various behavioral conditions and situations with hyperactive, emotionally disturbed, and learning disabled children. Results from the studies with hyperactive children indicated that drug treatment was effective only for formal settings (classroom, laboratory, etc.). The emotionally disturbed Ss showed deviant behavior to be affected by drugs, and classroom on-task behaviors increased with the use of methylphenidate in comparison with the placebo and thioridazine treatments. With the learning disabled, methylphenidate increased the number of correct responses concomitant with an increase in responding. Conclusions were drawn to the effect that methylphenidate enhances learning. (Author/IM)