This man took 25 hits of Molly (MDMA) every day for four years

A gentleman referred to in a scientific study as "Mr A" took 40,000 pills of MDMA (Molly, Ecstasy) in nine years. At his, er, peak, he was gobbling an average of 25 tablets per day. Guess what? It messed him up. In 2006, psychiatrist Christos Kouimtsidis published a case report in the journal Psychosomatics. From The Face:

Mr A didn't just use MDMA, he had a history of polydrug use ("solvents, benzodiazepines, amphetamines, LSD, cocaine and heroin") and was still smoking weed when he got help. Can we be sure that the pills alone caused this? ​"It's very difficult to establish a cause in medicine," Dr Kouimtsidis says. ​"You cannot say 100 per cent, but we can safely attribute the memory difficulties that he had experienced when I'd seen him to the heavy use of ecstasy for a prolonged period of time."

When the researchers did memory tests with Mr A, they concluded that he was suffering from ​"disorientation to time, poor concentration and short-term memory difficulties". He had to repeat activities several times and ​"his concentration and attention were so impaired that he was unable to follow the sequence of the tasks required". When he toned the weed down it ​"led to both the disappearance of his paranoid ideas and hallucinations and a reduction of his panic attacks". But the other symptoms remained[…]

What happened to Mr A in the end? ​"We were trying to get him into a residential unit for people with memory problems," Dr Kouimtsidis recalls. ​"And then he left that unit and disengaged from the services. That was 20 years ago."