"Once people convince themselves that the drug is the easy solution to their problems, they're on their way to low-level addiction."

This happens with any substance if a person isn't actually working through the issues that lead to them wanting to "escape" temporarily. However MDMA does have the function of actually giving people access to suppressed-repressed trauma/stress, and once having access makes it easier to process/heal - this is why it's powerful to eliminate PTSD.