When one is really tired and can't go to sleep, trys everything.. why can't they?

Depends: On your overall health. If sugar is important for you, it could be the cause. Sounds weird? I have seen so much ill health from the widespread sweet "junk" eaten and drunk today, if there is emotional stress, that could be related.

Variable: Reports abound about high sugar items eaten at night, but there seems consistency regarding orange juice and fruit juices which seem to cause insomnia in some. A number of medications could cause this. Sometimes fatigue confuses the issue and does not equate with sleepiness, and lastly, if unresolved stress, anxiety, or worry, may be a problem too. Try consistent bed time at 60 degrees.