Mild traumatic brain injury (MTBI) or concussion was first identified as a syndrome in 1866 by John Eric Erichsen when he described a syndrome of multiple symptoms occurring following minor or severe head injury. There is no widespread consensus on distinctions that may exist between the terms concussion and MTBI. A clinical syndrome characterized by immediate and transient alteration in brain function, including alteration of mental status and level of consciousness, resulting from mechanical force or trauma. Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces. Dysautonomia has also been identified as a potential complication following MTBI. Patients with persistent symptoms are said to experience postconcussion syndrome (PCS). Recommendations for use of a standardized management of concussion come from several credible sources, one of the most frequently cited being the Sport Concussion Assessment Tool 3 (SCAT3). Iatrogenic complications are associated with inexpert application of psychiatric medications.