MDMA affects many of the same neurotransmitter systems in the brain that are targeted by other addictive drugs. Experiments have shown that animals will self administer MDMA—an important indicator of a drug’s dependency potential—although the degree of self-administration is less than some other drugs of abuse such as cocaine.35
Few studies have attempted to assess MDMA dependency among users in the general population, and those that have been conducted have shown widely varying results, likely because of the different population samples and different types of measures used. We do know that some MDMA users report symptoms including: continued use despite knowledge of physical or psychological harm; tolerance (or diminished response); and withdrawal effects, such as fatigue, loss of appetite, depressed feelings, and trouble concentrating.
As a result of scientific research, we know that addiction is a disease that affects both brain and behavior.