Hello there, MDMA (Methylenedioxymethamphetamine) used as ecstacy, is know to cause multiple effects like mental stimulation,emotional warmth, enhanced sensory perception, decreases anxiety,elated mood, these are the effects which makes individuals use MDMA more often. At the same time there are a lot of undesired effects, like altered heart beat (arrythmias), high blood pressure,depressed mood, aggression, increased thirst , irritabilty., out of these high blood pressure, altered heart beat can cause dizziness. Apart from that other health conditions and being on other medications can cause potential side effects and serious life threatening complications as well. Hope this answers yours doubts.