I found this a facinating article. Could it be that some of us need to go to bed much earlier, and assume that we will be up for 2 hours in the middle of the night instead of trying to get more done late in the evening before going to bed?
This article points to the 8-hour night’s sleep as a recent creation brought about by electric lights and the need for “efficiency”. It makes the case for two 4-hour sleep periods per night being the natural human and historical norm.
I can say that sleep is the foundation upon which many of the mental health problems I see rest. A client with bipolar disorder is often much more stable when he/she can sleep during regular nighttime hours. A depressed and anxious client who can get some sleep is less depressed and anxious. And so on.