State-dependent learning in children receiving methylphenidate.

Methylphenidate state-dependent learning was investigated using a paired-associate learning task of 16 pairs of pictures. Subjects were 15 children for whom methylphenidate was currently being prescribed. Each child was seen for two learning sessions and two testing sessions. Learning took place under placebo and under the child's regular dosage of methylphenidate. During retention testing all combinations of learning drug-state and testing drug-state were observed for each child. Data were analyzed using contrast variables which took into account the repeated-measures nature of the design. The results indicated that there was a trend in the direction of state-dependence in the whole sample. Significant symmetrical state-dependent effects were obtained in those subjects whose original learning was facilitated by methylphenidate.