Acute MDMA and ethanol interaction effects on psychomotor performance

Abstract

Introduction: A considerable percentage of young people expose themselves to 3,4‐methylenedioxy‐methamphetamine (MDMA or ‘ecstasy’). Alcohol is relatively commonly used in combination with MDMA (Barrett et al., 2005). As a percentage of MDMA users admit to driving under influence (Riley et al., 2001), the assessment of the effects of co‐administration of these substances on psychomotor performance is warranted.Hypothesis: We hypothesized that the co‐administration of MDMA and ethanol would ameliorate the impairment induced by ethanol alone.Methods: We performed a double‐blind, randomized, placebo‐ controlled study in 16 healthy volunteers (9 male, 7 female) in the age of 18–29 years. MDMA 100 mg was given orally and blood alcohol concentration (BAC) was maintained at 0.6‰ by a three hour 10% alcohol infusion regime (adjustment of infusion rate according to regular sampled breath alcohol concentration). Saccadic and smooth pursuit eye movements, a validated measure of ethanol induced sedation (van Steveninck et al., 1999), were recorded using Nihon Kohden® and Cambridge Electronic Design (CED®) hardware and Spike2® software at 1 : 35 post drug administration. Results were statistically evaluated using GLM in SPSS® 11.5.Results: Results are presented in table 1. Saccadic peak velocity was increased after MDMA (p=0.000). Co‐administration showed significant increase in peak saccadic velocity compared to placebo (p=0.004), although significantly less then the increase as observed after MDMA alone (p=0.003). Smooth pursuit was significantly impaired after ethanol compared to placebo (p=0.000) and MDMA (p=0.000), co‐adminstration also impaired score compared to placebo (p=0.000) and MDMA (p=0.000). Eye movement scores per drug Eye movements Placebo Ethanol MDMA Ethanol + MDMA Mean SD Mean SD Mean SD Mean SD Peak saccadic ◆, ♠ *, •, ♠ *, •, ◆ velocity (deg/s) 458,1 66,1 452,8 54,8 543,5 76,3 497,2 65,8 Saccadic reaction time (ms) 190,8 25,3 194,4 26,1 193,0 24,9 191,6 24,9 Average smooth *, ◆ •, ♠ *, ◆ pursuit (%) 49,08 12,00 37,56 9,72 52,74 14,30 38,90 9,85 *=Significant vs. placebo, • =Significant vs. ethanol, ◆=Significant vs. MDMA, ♠ = Significant vs. MDMA + ethanol. Conclusions: MDMA induced arousal as measured by the saccadic peak velocity when administered alone and, to a lesser degree, in combination with ethanol. Co‐administration of MDMA with ethanol however could not ameliorate the deterioration of psychomotor accuracy by ethanol as measured by smooth pursuit eye movements. These findings suggest that although MDMA might ameliorate ethanol induced sedation it does not ameliorate impaired psychomotor skills. This might give a false sense of improved performance while intoxicated and thus increases risks of for example road accidents.