 I am Dr. Murali Raj and I am currently head of department of psychiatry here and I practice clinical psychiatry at the Manipal Hospital. It is often felt that lack of sleep causes depression but it is usually the other way around. When you are depressed we cannot sleep, either we go to bed to find it very difficult to go to sleep, start getting negative thoughts or sometimes we wake up early in the morning, say 2 or 3 am, we cannot get back to sleep and then all these thoughts flash in, all negative thoughts of the future, what is going to happen and things like that. So lack of sleep is more a consequence of depression than a precursor of depression.