A pilot study did not show that its hypothesized heart-rate-variability measure predicted creativity changes with stimulant medication. Some secondary associations appeared before correction for multiple testing, but did not survive that correction.
Adults with ADHD completed counterbalanced sessions on their prescribed stimulant medication and after abstaining for at least 24 hours. Prescriptions included amphetamine-class and methylphenidate-class medicines, so the study did not isolate an amphetamine-specific effect.
An eight-minute electrocardiogram preceded convergent anagram tasks and divergent-thinking tasks. Heart-rate variability described variation between cardiac beats; it was not a direct measurement of brain dopamine or norepinephrine.
The hypothesized pNN50 measure did not predict stimulant-related changes in convergent or divergent creativity. None of the examined autonomic predictors significantly predicted changes in anagram performance.
Selected frequency-domain measures showed nominal associations with divergent-thinking components such as fluency, flexibility or originality. Those secondary findings did not survive multiple-comparison correction. Reporting only their uncorrected p values would misrepresent the strength of the evidence.
Failure of a cardiac proxy to predict performance does not prove that one neurotransmitter system is irrelevant or another is responsible. Such mechanisms require more direct measurements and adequately powered designs.
The sample was very small, treatments varied and a medication-abstinence comparison differs from a blinded placebo-controlled dosing experiment. The result does not validate an HRV-based prescribing tool or prove broad creative enhancement. Nor can cardiac variability identify amphetamine concentration or individual impairment.
See the separation of subjective stimulant responses.
Heart Rate Variability Prediction of Stimulant-Induced Creativity Gains in Attention-Deficit/Hyperactivity Disorder. doi:10.3390/jcm14103570.