Insomnia

Insomnia is a common disorder in the Autism community and is characterized as not being able to fall asleep or waking up intermittently during the night. I like many others on the Spectrum suffer from chronic insomnia, which is when insomnia lasts for multiple nights that can last months or years at a time. The causes vary but I am just going to focus on two of them in this post, and those would be insomnia caused by stress and sensory issues. 
Stress can be caused by many things in the life of an individual on the Spectrum. The main one I believe would be thinking about whether or not one communicated effectively during the day. I say this because of all the nights I have been up trying to recap the day and determine how effective my communication was during that day. Whether it was: stating my phrases correctly, so to not offend others by missaying something; reading verbal cues correctly, to see if a person was actually interested in what I had to say or if I was going on and on about a certain topic to the point I ended up annoying someone, and hearing fluctuations correctly, to be able to know if someone was being sarcastic about something and whether my response was appropriate or not. As your probably thinking, this can get very long if I had quite the sociable day. It gets even longer if I wonder off thinking about random topics and what if scenarios, which both add on to the stress of living on the Spectrum.
However I do want to give a theory of stressed related insomnia since a lot of kids on the Spectrum have insomnia and I know I really did not think about social interactions till I was well into my teens. The theory is that with these kids that have insomnia, is that they have no idea what is going to happen to them if they fall asleep and thus are stressed out about that to the point sleep is no longer a option. This theory of course is a better fit for those that have sensory issues.
Imagine this, throughout the day you are bombarded by lights, noises, things that come into physical contact with you, tastes, and smells. Then its night time and you essentially turn off three of those senses. Those being sight, taste, and physical contact of things. That leaves you with hyper sensitive listening and smelling, if you believe senses heighten due to loss of other senses and I do. How can anyone expect to sleep if every little noise sounds ten times louder and ever smell is ten times stronger? It is near impossible because I personally have very sensitive ears at night and every little noise that is not repetitive long enough will just keep me up. This comes from someone with very little sensory issues, just imagine what it might be like for someone who has major sensory issues, aka sensory processing disorder (not deemed a disorder by doctors, by the way). 
With all this being said, one would think the next paragraph would be on solutions to this problem. Well, unfortunately I am still looking for one myself and am not a licensed physician to do so. All I can say is that exercise and a proper diet(like no caffeine at night) can help influence your system to relax naturally at night time to help deal with the stress of living on the Spectrum. But I am not one to say no to suggestions, so what have you found to help you/your child/ someone you know to end their cycles of insomnia?