The human neurotoxicity experiment in the United States is scientifically complicated by the difficulty of creating control groups that exactly match the MDMA using group in all respects except the use of MDMA. Serotonin levels vary 300% in the normal population, and personality, diet and other factors play major roles in the variance. An ideal study design would have subjects acting as their own control, being tested at two points in time with administration of MDMA occurring between tests. This type of study is not permitted yet in the United States but is possible in Switzerland. In order to gather necessary data, the psychiatrists of the Swiss Psycholytic Association volunteered to collaborate with Dr. Ricaurte on a neurotoxicity study, even though the Swiss government has not specifically requested the study. Swiss subjects will donate spinal fluid before and after multiple treatment with MDMA, permitting the establishment of pre-MDMA levels. Sample analysis will be conducted by Dr. Ricaurte.