Alterations in the vigilance performance of children receiving amitriptyline and methylphenidate pharmacotherapy.

The effects of amitriptyline (Elavil) and methylphenidate (Ritalin) on the vigilance of 20 hyperactive/aggressive children was investigated using an auditory version of the Continuous Performance Test (CPT). Over the course of this letter-detection task, correct detections tended to return to pretreatment levels under placebo, but were maintained at significantly improved levels under amitriptyline and methylphenidate. The relatively steep performance decrement which occurred in the placebo condition was found to be associated with a progressive increase in responses to the letter which immediately followed a target letter. Treating these 'late' responses as slow but 'correct' detections failed to eliminate the treatment effects obtained with amitriptyline and methylphenidate. It was concluded that in addition to keeping detection response latencies from increasing, the medications produced a heightened level of vigilance which resulted in an absolute increase in the number of correct detections. The facilitation of vigilance performance by amitriptyline was in apparent contradiction to reports by parents and teachers that children appeared 'drowsy' while receiving this medication. Findings of the study suggested that children's ability to process information was unaffected by the reported side effect.