Traumatic Brain Injury

DEFINITION

• Traumatic brain injury (TBI) is most simply defined as damage to the brain from trauma to the head from a source outside of the brain.
• The Centers for Disease Control and Prevention (CDC) defines the cause of TBI as a bump, blow, or jolt to the head or a penetrating head injury that disrupts the normal function of the brain (http://www.cdc.gov/traumaticbraininjury/).
  • It is important to remember that not all blows or jolts to the head result in a TBI.

• Severity of TBI is rated at the time of injury/initial assessment as mild, moderate, or severe according to Glasgow Coma Scale (GSW), duration of loss of consciousness (LOC), and/or duration of posttraumatic amnesia (PTA) (see Table Severity of TBI)[1].
  • Importantly, the severity rating of the TBI itself does not necessarily correspond to the severity of the resulting psychiatric phenomena.

• Psychiatric disorders that may result from TBI are wide-ranging and include mood disturbances, psychosis, cognitive disturbances, and behavioral disturbances.
  • Certain symptoms such as sleep disturbances, fatigue, apathy, and pathological laughter / crying may occur in isolation rather than as part of a psychiatric syndrome.
• Although as described below TBI can have a number of psychiatric sequalae, the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) only includes cognitive impairment due to TBI, which is classified in the neurocognitive disorders (NCDs) section[1].