Functional Brain Imaging in Recreational Users of Ecstasy

Overview

Recreational use of "ecstasy" (MDMA; 3,4-methylenedioxymethamphetamine) is associated with long-lasting effects on metabolism in the human brain. The investigators propose to investigate whether chronic use of "ecstasy" is associated with impairment in motor skills and function of the dopaminergic system in recreational users of "ecstasy" compared with healthy volunteers. This will be done by scanning control subjects and "ecstasy" users at baseline and after performing on a motorbike riding computer game, while imaging dopamine in vivo with I123-IBZM (a D2 receptor radiotracer), using single photon emission computed tomography (SPECT).

Recreational use of "ecstasy" (MDMA; 3, 4-Methylenedioxymethamphetamine) is associated with long-lasting effects on metabolism in the human brain. In particular, there is evidence of long-term damage to the brains' neurotransmitter serotonin (5-HT). It is also known that chronic use of Methamphetamine (which is similar in its chemical structure to "ecstasy") is linked to impaired cognitive and motor skills despite recovery of dopamine transporters (DAT). We have investigated whether chronic use of "ecstasy" is causing any impairment in motor skills and function of the dopaminergic system in recreational users of "ecstasy". In our preliminary study, we have scanned control subjects and "ecstasy" users, at baseline and after performing on a motorbike riding computer game while imaging dopamine in vivo with \[123I\] IBZM (a D2 receptor radiotracer) in Single Photon Emission Computed Tomography (SPECT). We showed: 1. Lower measures of D2 at baseline in ecstasy users compared with control subjects, that means lower level of dopaminergic activity in "ecstasy" users. 2. Significant displacement of \[123I\] IBZM by endogenous dopamine released during the game in healthy subjects unlike "ecstasy" users, that means that recreational users of "ecstasy" release much less natural dopamine. 3. No difference between the groups in performance (reaction time) on riding the game after a year of recovery. Our results show preliminary evidence for dopaminergic deficiency in "ecstasy" users, a finding that has not been shown before. However, similar to other drugs of abuse, it is not known whether dopaminergic deficiency is the cause or consequence of the use of "ecstasy". We now propose to proceed to scan more recreational users of "ecstasy" in order to assess whether chronic use of "ecstasy" is associated with deficient dopaminergic neurotransmission in the brain.