MDMA and temperature: a review of the thermal effects of 'Ecstasy' in humans.

AIMS To review the thermal effects of MDMA in humans, and discuss the practical implications. METHODS The literature on Ecstasy/MDMA, body temperature, and subjective thermal self-ratings was reviewed, and explanatory models for the changes in thermal homeostasis were examined and debated. RESULTS In human placebo-controlled laboratory studies, the effects of MDMA were dose related. Low doses had little effect, moderate doses increased body temperature by around +0.4°C, and higher doses caused a mean increase of +0.7°C. With Ecstasy/MDMA using dance clubbers, the findings showed greater variation, due possibly to uncontrolled factors such as physical activity, ambient temperature, and overcrowding. Some real world studies found average body temperature increases of over +1.0°C. Thermal homeostasis involves a balance between heat production and heat dissipation, and MDMA affects both aspects of this homeostatic equation. Cellular metabolic heat output is increased, and heat dissipation mechanisms are stressed, with the onset of sweating delayed. Subjective responses of 'feeling hot' or 'hot-cold flushes' are frequent, but can show individual variation. Some recreational users report that heat increases or reinstates the positive mood effects of Ecstasy/MDMA. The dangers of acute hyperthermia can include rare fatalities. It is unclear why moderate hyperthermia can occasionally progress to severe hyperpyrexia, although it may reflect a combination or cascade of events. In chronic terms, the bioenergetic stress model notes that the adverse psychobiological effects of MDMA are heightened by various co-stimulatory factors, including heat stress. CONCLUSIONS MDMA increases core body temperature and thermal stress in humans.