It appears the drug ketamine \u2013 known as \u201cK\u201d or \u201cSpecial K\u201d \u2013 is increasing in use faster than any other drug in the UK. This finding is from the British Crime Survey, 2008 and featured in a recent Science Daily release. The British Crime Survey is the first ever, large-scale, longitudinal study of ketamine users which shows the consequences of repeated ketamine use. To conduct their study, researchers from the University College London followed 150 people over the course of a year to see if changes in their ketamine use could predict changes in their psychological well-being, memory and concentration. Of the 150 studied, 30 were taking large quantities of the drug almost every day; 30 were taking it recreationally \u2013 which meant once or twice a month; 30 were former users; and 30 used illicit drugs apart from ketamine. A final 30 participants did not use any illicit drugs. Researchers found that the heavy ketamine users were impaired on several measures, including memory. At the same time, hair analysis showed that use among recreational users doubled at follow-up compared to initial testing. While levels did not increase across the frequent users group, these individuals were already taking as much as ten grams per day. Those who used ketamine recreationally and ex-users did not differ from non-drug users in the control group in relation to memory, attention and psychological well-being. All groups of ketamine users, however, showed evidence of unusual beliefs or mild delusions. Lead author Dr. Celia Morgan said in Science Daily,: "These findings have implications for the growing number of ketamine users in the UK as well as addiction professionals who may encounter increasing numbers of ketamine dependent users. These findings suggest these frequent ketamine users will be impaired, albeit transiently, in a variety of psychological domains."