A form of the hyperkinetic syndrome, assumed to be a juvenile condition, has been found in an adult with a previously undiagnosed condition. The pathognomonic paradoxical calming of the hyperkinetic by amphetamine was shown in a 22-year-old man and further elucidated by quantitative self-estimation of mood following doubleblind administrations of dextroamphetamine sulfate and placebo. Compared to his response to placebo, he not only showed externally visible calming and depression, but also subjectively reported decreased anxiety, increased depression, and increased concentration, with no change in self-esteem.
Arnold LE, Strobl D, Weisenberg A. Hyperkinetic AdultStudy of the "Paradoxical" Amphetamine Response. JAMA. 1972;222(6):693–694. doi:10.1001/jama.1972.03210060047012