I'm suprised that he had to return a week later for another session. MDMA tolerance should be counted as a huge factor. I'm not sure if this is accidental or not. Although 83mg is not a big dose, and shouldn't be neurotoxic, without any supplements like 5-htp or other precursors to serotonin, it's pretty tough for your serotonin levels to return to baseline in a week time.
I don't know all of the protocol involved in the testing process but as Nutt is involved I think they're possibly trying to simulate the real world effects of repeat usage, the average user wouldn't be aware of 5-htp.
