It’s insomniac. Most people have this and will stay away for days. Typical human being required sleep 6hours a night at least and sometime rest or nap during the day. However this man, haven’t been sleeping for over 40 years? How do we know if it’s true? well I did some research and found different sources such as wikipedia and the local news in Vietnam interviewed him and published many related articles, it was due to insomnia that cause a person to cannot sleep, but some article indicate a person will died after 9 days if he/she cannot sleep, but this man over 40 years, that’s a lot. Well the last article I read about this person, it indicated that “In October 2006, however, Ngoc reported that he was beginning to feel “like a plantwithout water” due to the lack of sleep.”