There is an article in the December 30th edition of the New England Journal of Medicine that concludes that general anesthesia is a drug-induced coma and not sleep. Anesthesiologists apparently know this and tell patients they are putting them to sleep because they know that telling patients they are putting them in a coma might be too scary.
Three neuroscientists came to the conclusion after reviewing the data. This is interesting because the data show that coma and the effect of anesthesia are similar. By studying the drug-induced coma of anesthesia, researchers might learn more about how to help patients recover from a coma.
Even though anesthesia may not be sleep, some of my patients with insomnia remark that the best sleep they ever got was under general anesthesia. Studying those individuals would be interesting too. Remember, Michael Jackson died in part because of using general anesthesia to induce 'sleep' in his home. Very dangerous.