In a double-blind study, time production tasks and clinical tests of memory function were performed by 15 normal subjects given placebo and "social" doses of alcohol (ethyl alcohol) and marihuana, calibrated to (-)-δ1-tetrahydrocannabinol. Using subjects as their own controls, it was found that, compared to alcohol and placebo, marihuana induced a significant under production of time intervals suggesting an acceleration of the internal clock. At these dose levels, there were no significant changes in memory function, but during marihuana intoxication some consistent trends toward greater impairment of tracking information over time were noted.
Jared R. Tinklenberg, Bert S. Kopell, Frederick T. Melges, Leo E. Hollister. Marihuana and AlcoholTime Production and Memory Functions. Arch Gen Psychiatry. 1972;27(6):812–815. doi:10.1001/archpsyc.1972.01750300074013