MDMA has little addiction potential- for one it isn’t really just an unhealthy escape from negative feelings, but helps people process traumatic experiences and negative emotions by temporarily lowering anxiety and fear, and may be close to being FDA approved for that therapeutic purpose.

I have only tried it once, and it permanently eliminated my crippling social anxiety, by temporarily eliminating it, and allowing me to experience and remember what that was like. I felt no desire to use it again, because the (life changing positive) effect was permanent.

Second, it seems to have rapidly diminishing effects that make it self limiting- if sometime takes MDMA too much or too frequently, it stops having the desired effect.