k or had taken psychotropic medication, for the same reason. The MDMA group was composed of persons who said they had used MDMA on at least 20 occasions. The comparison group was made up of subjects who had never used MDMA and didn’t use cannabis regularly. The last group, the cannabis group if they had used cannabis at least twice a week for at least a two-year period, and MDMA only irregularly.The subjects all signed consent forms and were administered the National Adult Reading Test (21) to obtain estimated IQ. They were then fitted with an electrode cap using tin electrodes.) and were then placed in an electrically shielded sound-attenuated booth, to see what their hearing thresholds were. The subjects then filled out a series of questionnaires about personality and drug use. At the same time the intensity dependence paradigm was run. (Duration=15 minutes.)The data was collected an analyzed. The Kruskal-Wallis nonparametric test was used to test for differences between the intensity dependence slopes of the three groups. They then used the Nondirectional Mann-Whitney tests to do the post-hoc analyses. To make sure that the group differences were from MDMA user’s MDMA use and not other variables, data for the MDMA group were analyzes with a multiple regression in which N1/P2 slope was the criterion and the total MDMA consumption (tablets), frequency of MDMA use (tablets per month), age, and sex were the predictor variables. The variable “total MDMA tablets used” was transformed to normality by using the square root function (yielding t_total) and “frequency of use” was transformed by using the natural log (yielding t_frequency.) A correlation analysis was performed to determine if t_total and t_frequency were related.So what was the outcome recorded by the statistical and data analysis? Well, significant positive relations were found between MDMA users’ N1/P2 slopes and total M...
