Mdma, sporadic success rates. Stumped

[pankreeas]

Swim started using mdma for the first time last year and has a handful of successes but also near as many failures. For his first time he opted for a dose which at the time was 85mg mdma powder dissolved in juice and only a very slight effect that placebo effect could easily cause was the extent of his trip. Then a few months passed and he again tried... 2 pills.. nothing again. And it was mdma... no questions regarding the source being bunk as all others got effects... then all of a sudden one day after a binge on coke and opiates he popped 1 pill for the heck of it and he finally "got off" on E... and it was amazing. 2 months later he again did 1 pill after a binge but nothing.. then same night he took another pill 2 hrs later and once again got the real deal... then since its been another 2 good 2 bad... and now again swim is back after 5 months off... with 200mg to start... and nothing. Anyone else experience this phenomenon? oh btw swim was using the E this time to come off the coke... is that the issue right there? dopamines rather tilted power balance over seratonin? swim is stumped as he never done near enough in terms of dose as well as occasions to warrant a tolerance...