Reliability of Standardized IQ Testing Under Modafinil, Racetam-Class Compounds, Sleep Restriction and Daily Activity

This study examined whether standardized IQ test scores in healthy adults aged 18-35 are stable measures of cognitive ability and evaluated whether standardized cognitive-test performance and response-initiation measures vary across pharmacological and sleep conditions. Seventy healthy volunteers were assessed at seven in-person timepoints over six months, with 25 participants receiving an inert matched preparation and 45 receiving modafinil or one of four racetam-class compounds (oxiracetam, pramiracetam, phenylpiracetam, aniracetam) administered orally before testing. A different standardized instrument was administered at each timepoint to limit item-level recall and practice effects, and change in the placebo group was used as the reference for estimating practice effects. Participants were assessed under both rested and sleep-restricted conditions, two psychologists were present at every administration to code response initiation (hesitation), and physiological state was monitored using a consumer wearable. Psychometric changes were evaluated relative to the standard error of measurement of the instruments and the study's prespecified minimum detectable effect. Response-initiation measures were analysed separately from psychometric scores to evaluate potential effects on response initiation and execution time.