Bladder shrinkage affects young ketamine users even in the early stages, doctors say, contradicting earlier assumptions that the condition appeared only after years of abuse of the popular party drug. Chinese University researchers made the discovery based on health checks on volunteer drug users in North District in the past two years. 'We hope the findings will enhance public understanding of the harmful effects of drug abuse and will motivate abusers to seek cessation,' said principal researcher Dr Mak Siu-king, a urologist at the university's faculty of medicine. He said the research proved it was a misconception that only those who had been taking the drug for many years would get urinary problems. The researchers found users could recover spontaneously after they quit the drug, although longer-term users developed scarring that made recovery difficult. Data collected in 2009 showed that ketamine users with at least a two-year habit of three or more hits a week had smaller bladders that forced them to go to the toilet and caused them pain. Ah Chun, 25, started taking drugs when he was 11 and quit last year. 'Now I usually need to use the bathroom once every hour - before it was once every 15 minutes,' he said. He quit after tests found that his bladder capacity was just 90 millilitres compared with the normal capacity of 400ml to 500ml. Of the 66 participants in the research, with an average age of 18, those taking ketamine three, four and five times weekly had average bladder volumes of 203.2ml, 199.6ml and 189.5ml respectively. 'We can see that the more frequently they take the drug, the more their bladder shrinks. Its function is already degrading,' Mak said. Young people who had quit for more than one year had an average bladder capacity of 387ml compared to 243ml for those in their first three months of rehab. Comparing former users in their first year of rehab showed that their symptoms would progressively decrease in severity. 'Some [users] ask us what medicine they can take for bladder recovery. We tell them: once you quit the habit, it will get better,' Mak said. The link between ketamine and bladder weakness is long-established. Another Chinese University study released earlier this month revealed that former users may still have weak bladders eight months after kicking the habit.