Toxicological Trivia from May 05, 2010: Ketamine, sometimes popularly known as "K" or "Special K", is used primarily as a veterinary anesthetic. In humans, it causes hallucinations and hypertension. A single dose of ketamine can cause psychotic effects and problems of thought, wrote the team of Dr. Celia J. A. Morgan, of University College London, in the journal Addiction, in November 2009. However, it was clear the impact of repeated use over the long term. The powerful anesthetic ketamine abuse is increasing in many countries and now an investigation shows that the repeated use of this drug:
a) damages the memory
b) alters the concentration and psychological well-being;
c) Both previous assertions are correct.

Correct answer c. Read more in article:  Memory problems with ketamine