Researchers from London University have revealed details of a man who claims to have taken 40,000 ecstasy pills over nine year period.
This is the largest amount of ecstasy ever reportedly consumed by a single person and the consultants from the addiction centre at St George's Medical School, London, have published a case report on it.
MDMA, the active ingredient in ecstasy, is one the most intensely studied recreational drugs in history but scientific evidence on the side-effects remains inconclusive.
It is thought to cause over-heating which in turn, in rare cases, can trigger fatal heat stroke; water-poisoning when users, fearing they are overdosing, drink too much water and provoke hyponaetraemia (water-poisoning); and depression - many weekend users report a mid-week mood dip.
This is suspected to be related MDMA's effect on serotonin.
The 37 year old man stopped taking the drug seven years ago, but still suffers from severe physical and mental health side-effects, including extreme memory problems, paranoia, hallucinations and depression.
He also has painful muscle rigidity around his neck and jaw which often prevents him from opening his mouth.
Many of these symptoms may be permanent.
The researchers believe his condition could indicate the use of ecstasy leads to irreversible memory problems and other cognitive defects.
Apparently following three episodes of 'collapsing' at parties, the man finally stopped his ecstasy use.
Episodes of 'tunnel vision', severe panic attacks, recurrent anxiety, depression, muscle rigidity, functional hallucinations, and paranoid ideation continued.
Tests revealed memory impairment and "major behavioural consequences of his memory loss" such as repeating activities several times.
Although his long-term memory was fine he could not remember day to day things and seemed unaware he had memory problems.
With no mental illness in his family and no prior psychiatric history, the doctors concluded that his unique condition was direct result of his intense ecstasy use.
For many years, MDMA has been suspected of causing such effects in heavy users, thought to be due to the disruption of the regulation of serotonin, a brain chemical believed to play a role in mood and memory.
It remains unclear whether these effects are the result of permanent neurotoxic damage or just temporary reversible alterations in the brain.
When admitted to a specialist brain injury unit and given anti-psychotic medication, he showed some improvement but unfortunately discharged himself before an assessment was able to be completed.
A study from the University of Louisiana says users claim benefits such as long lasting improvements in self-awareness, self-esteem, openness and insight into personal problems.
The researchers could find no significant relationship between depression and recreational ecstasy use.
The study is published in a special MDMA issue of the British Journal of Psychopharmacology, suggests long-term side-effects may be temporary.
In the U.S., research continues into the use of MDMA-assisted psychotherapy to treat Post Traumatic Stress Disorder.