This study will test if patients with moderate to severe traumatic brain injuries also have endocrine abnormalities, examine any existing relationships among fatigue, depression and endocrine abnormalities, and the relationship between endocrine abnormalities, quality of life, and community integration.

Inclusion Criteria:

• Having moderate to severe TBI at least 3 months prior to enrollment. This can be demonstrated by a history of loss of consciousness, amnesia or another neurologic deficit after brain injury
• Be between the ages of 18 and 70 years

Exclusion Criteria:

• History of prior TBI, stroke, seizures, severe psychiatric disturbances (i.e., those known to influence memory performance, such as schizophrenia, bipolar disorder), or drug abuse will be excluded.
• Pregnant, nursing, or planning pregnancy during the study period.
• Dementia
• Other neurological conditions which are associated with aging and known to cause fatigue (e.g. Parkinson's Disease)

The study will consist of 50 participants taken from the outpatient brain injury program at Kessler.