Influence of Lysergic Acid Diethylamide (LSD-25) on Subjective Time

Introduction: Various reports have shown that the subjective sense of time can be considerably altered through changes in the external circumstances under which the judgment is made. Somewhat less is known of the influence of the subject’s physical state on his ability to estimate time. This lack may be at least partially due to the fact that most conditions, such as fever or delirium, which have been described as bringing about such changes often simultaneously make it difficult or impossible to collect systematic data. When physical states are experimentally induced, however, the effects can be better controlled and tested. In this way, information has been obtained on the influence of nitrous oxide and mescaline on the sense of time. The very striking effect of lysergic acid diethylamide (LSD-25) on the sense of time has been described in various ways by those who have observed the reaction: Time sense . . . was characterized by the feeling of being accelerated or retarded ; Not only is there impaired ability to estimate the passage of time, but there is also a sense of timelessness.Methods: Twenty-four subjects were used as their own controls to determine the effect of lysergic acid diethylamide (LSD-25) on the subjective passage of time.Results: Under the drug the subjects overestimated the stimulus intervals to a significant degree, indicating that the drug has the effect of making time appear to pass more slowly than usual.Discussion: The results of this study were unlike those reported in an earlier experiment, in which no consistent changes were found under the drug. Differences between experimental procedures were discussed to suggest reasons for the divergent results. The findings were examined for theoretical implications in light of other changes noted as common to the LSD-25 reaction.