This protocol is designed to screen and detect evidence of pituitary hormone deficiency in adults following traumatic brain injury. Treatment period for thyroid or cortisol deficiency will be six months. Growth hormone deficiency will be replaced for a period of one year followed by a second year of open label treatment to allow individuals in the placebo group an opportunity to demonstrate a response to hormone replacement. Subject will not be screened until at least one year following brain injury to allow for natural recovery of hormone function.