What notable exception exists for hallucinogens regarding withdrawal and dependence?

MDMA, commonly known as ecstasy, is notable among hallucinogens because it is associated with a greater potential for withdrawal symptoms and dependence compared to other substances in this category. Unlike classic hallucinogens such as LSD, psilocybin, and peyote, which typically do not produce significant physical dependence or a withdrawal syndrome, MDMA can lead to a range of psychological and physiological withdrawal symptoms upon cessation after regular use. These may include fatigue, mood disturbances, and changes in appetite, making it distinct in this context.

MDMA's pharmacological effects involve the release of serotonin, dopamine, and norepinephrine, which can result in a reinforcing cycle leading to regular use and potential dependence, distinguishing it from traditional hallucinogens. The unique profile of MDMA's effects and the potential for addiction contribute to its classification as having withdrawal and dependence features, aligning it more closely with stimulant drugs than with classic hallucinogens.