I keep a look out for any information I can find on insomnia.  This article covers some of the information that matches my experiences.

http://www.complexptsd.info/Insomnia-and-PTSD.html

I am always looking for ideas that help.  Unfortunately, getting more sleep means an increase in nightmares.  Ugh.

The other way I use lack of sleep is to keep anger under control.  Only 4 hours of sleep a night leaves no energy to get pissed over anything.  Depression, anger without enthusiasm.