In previous ESP experiments by other researchers, various substances active on the central nervous system were administered to the subjects; namely, alcohol(1), caffein( 2), barbiturates and stimulants(3). It has been difficult to gather significant information from these works, because no efforts were made to achieve standardization of methods concerning the assessment of the personalities involved and of the effects of the dmgs used. Actually, in most of the past experiments with selected subjects, with or without drugs, medical and psychological investigation of personality was generally limited and often entirely lacking. There is no doubt, however, that the subject’s personality, with its variables, plays a fundamental role in ESP experiments, even if no positive and direct correlations have yet been found between any of its aspects and the phenomena under study. Therefore, we regarded as justifiable the collection of a large amount of data _on each subject, and the standardization of this procedure. We consider it essential to future research of this kind. When psychotropic drugs first became available, i.e. substances endowed with a specific action on mood and/or mental activity(4), several open-minded scientists made self-experiments with them, especially with psychodysleptics (drugs disrupting personality balance) in order to gain better insight into the dynamics of human personality. Many researchers administered these drugs to the nomial, to psychotics and neurotics in the hope of gaining a better understanding of the mechanisms of distortion of mental processes(5). In this way, a great deal of valuable material on the structure and function of the human personality was collected(6); however, as far as we know, no attempt has been made to study the possible occurrence and the conditioning of ESP phenomena under the effect of such drugs. Meanwhile, reports dealing with the possible mechanisms underlying telepathic occurrences between analyst and patient, during psychoanalytical treatment( 7), had paved the way for such an investigation. In this preliminary approach we have tried to outline a methodology for an extensive investigation of the occurrence and conditioning of ESP phenomena in humans during specific personality states. These states were induced by the intake of substances known to have well-defined, controllable, transient, and pharmacologically reproducible impact on the central nervous system, resulting in reversible alterations of personality; such alterations were studied prior to the experiments and thoroughly assessed with the means of dynamic psychology.