Doctors believe a man who claims to have taken 40,000 ecstasy pills during his lifetime is the biggest recorded user of the drug, it emerged today.
The 37-year-old, known as Mr A, still has trouble working out the time of day or knowing what is in his supermarket trolley despite having stopped taking it seven years ago.
At the height of his drug use he was consuming 25 pills every day.
Researchers from London University believe his condition could indicate the use of ecstasy leads to irreversible memory problems and other cognitive defects.
A letter to the journal Psychosomatics reported that Mr A used MDMA between the ages of 21 and 30.
For two years, he took five tablets every weekend, rising to 3.5 tablets for the next three years, and to 25 tablets a day over the next four years.
The letter, in February’s issue, said: "After three episodes of `collapsing’ at parties, Mr A finally stopped his ecstasy use.
"For a few months, he felt as if he was still under the influence of ecstasy and suffered several episodes of `tunnel vision’.
"He eventually developed severe panic attacks, recurrent anxiety, depression, muscle rigidity (particularly at the neck and jaw levels), functional hallucinations, and paranoid ideation."
When he presented himself to the addiction centre at St George’s Hospital, Tooting, south London, he was still using cannabis, and said he had previously taken solvents, benzodiazepines, amphetamines, LSD, cocaine, and heroin.
There was no mental illness in his family and no previous psychiatric history.
Tests revealed memory impairment and "major behavioural consequences of his memory loss" such as repeating activities several times.
"Although Mr A was able to fully understand the instructions given, his concentration and attention were so impaired that he was unable to follow the sequences of the tasks required," the letter said.
The doctors said it was the largest amount of ecstasy lifetime consumption described, the previous being around 2,000 tablets.
Dr Christos Kouimtsidis, the consultant psychiatrist at St. George’s who treated him, told the Guardian: "He came to us after deciding he couldn’t go on any more. He was having trouble functioning in everyday life.
"This was an exceptional case. His long-term memory was fine but he could not remember day to day things – the time, the day, what was in his supermarket trolley. More worryingly, he did not seem aware himself that he had these memory problems."
He added: "This is probably an extreme case so we should not blow any observations out of proportion.
"But if this is what is happening to very heavy users, it might be an indication that daily use of ecstasy over a long period of time can lead to irreversible memory problems and other cognitive defects."