I have suffered from insomnia since I was 10 years old. I have a lot of trouble falling asleep. Once asleep, I am all right, but it is a light sleep and I awake easily and then have the same trouble falling back to sleep.
I went to a sleep clinic once. They did not hook me up to all the wires and watch me sleep or not sleep. Instead they determined that I had physco-phisological sleep disorder. in other words it was either something physical or it was all in my head. That pretty well covered the waterfront.
Around 55 I started, under a doctor's supervision, using a sedative to fall asleep. I have to change them often because I build up a resistance to them and have to use something else for awhile.
For the record, I cannot sleep with my glasses on so I cannot read myself to sleep.
If I stay up later, I still spend two or three hours falling alseep. With the sedative and on a good night, I will get five to six hours of sleep. Often it is less than five an every now and then it is zero hours.