2. InsomniaInsomnia is simply the inability to fall or stay asleep. It also describes sleep that is unrefreshing and of poor quality. It may occur over the short-term, often as the result of an identifiable stressor, and be called acute insomnia. It also may become a more chronic condition. Insomnia can lead to great distress, and in exceptional circumstances it may be fatal (such as in fatal familial insomnia). Fortunately, there are many treatment options available.
It is quite possible that you can't sleep because your body desires to sleep at the wrong time. This is the case in those individuals with circadian rhythm disorders. The circadian rhythm refers to the natural pattern of the body's functions, including the drives for hunger and sleep. Most people desire to sleep overnight. However, if your circadian rhythm is shifted early (as in advanced sleep phase syndrome) or late (as in delayed sleep phase syndrome) your desire to sleep will likewise shift.
For those with delayed sleep phase syndrome, this may mean that you are a night owl and it will be difficult for you to fall asleep at an earlier time. You will likely lie in bed awake for hours at the start of the night, but then have difficulty getting up in the morning. This condition may be effectively treated with melatonin, a light box (phototherapy), or even behavioral therapy.