The older article below discusses the fact that a large amount of patients diagnosed with CFS have hormone/endocrine disfunction. Also gives examples of treatments giving patients relief. This is also relevant to Post Concussion Syndrome sufferers as they also can have this issue. People need to get their hormone levels checked. This is not normally done so you may never know.

How doctors are failing to spot the brain injury that could be behind 3�,��� cases of 'chronic fatigue' | Daily Mail Online

As this article states its common to have a hormone imbalance/disfuction after a mild or greater impact to the head and its often missed. If you have had any level of concussion thats yet another reason to get checked.

My son a PCS sufferer was treated for hormone imbalance years after when we had him checked for it and its made a world of difference. See my other posts.