Created for veterinary use, ketamine was originally developed to knock-out horses, but became increasingly accessible to drug users throughout the 90s.

Like many drugs that became popular in the 90s, the extent of its long-term damage is only now - a decade or so later - becoming apparent.

Speaking to BBC's Newsbeat, doctors reported an increase in new evidence that supports claims that the drug is causing symptoms ranging from serious stomach pains to incontinence among once-ketamine users

Doctor Angela Cottrell, who is researching the link between ketamine and bladder damage at the Bristol Urological Institute, said:

"People need to be more aware of this, the short-term effects can be severe enough but we just don't know what the long term effects are."

Right now, ketamine is considered a Class C drug, but there are speculations that it could be upgraded to Class B and studies like the one conducted by Dr. Angela could well help support this upgrade.

Ketamine use has reportedly doubled in a single year amongst 16-to-24 year olds who still consider it a "clean drug". The common perception amongst young drug-takers is that Ketamine can't ‘mess up your body’, but what they don’t realise is that, in extreme cases, the drug can cause lasting damage in the long-run.

A handful of ex-ketamine abusers have needed an operation to have their bladders removed leaving them incontinent for the rest of their life. Whilst a link hasn’t yet been scientifically proven, there is a worrying correlation between ex-users and people suffering bladder and incontinence problems. Enough to indicate that there is indeed a link between incontinence and the drug itself.