Post-concussion syndrome
Though no universally accepted definition of postconcussive syndrome exists, most of the literature defines the syndrome as the development of at least 3 of the following symptoms: headache, dizziness, fatigue, irritability, impaired memory and concentration, insomnia, and lowered tolerance for noise and light. One complication in diagnosis is that symptoms of PCS also occur in people who have no history of head injury, but who have other medical and psychological complaints. In one study 64% of people with TBI, 11% of those with brain injuries, and 7% of those with other injuries met the DSM-IV criteria for post-concussion syndrome. Many of these PCS sufferers were misdiagnosed as having other unrelated conditions due to commonality of symptoms. (see diagnosis, below).
Posttraumatic stress disorder and substance use disorders
Posttraumatic stress disorder (PTSD) can affect about 3.6% of the U.S. population each year, and 6.8% of the U.S. population over a lifetime. 8.4% of people in the U.S. are diagnosed with Substance Use Disorders (SUD). Of those with a diagnosis of PTSD, a co-occurring, or comorbid diagnosis of a SUD is present in 20-35% of that clinical population3 Prevalence of SUD and PTSD may increase depending on specific populations. For example, the prevalence of both PTSD and SUD is higher in combat veterans. Of those with a SUD diagnosis, current PTSD is present in 25-50%, and lifetime PTSD is present in 15-40%, averaging 30% overall. Though roughly a third of all people diagnosed with SUD also have PTSD, there is not yet consistent protocol for SUD treatment centers to screen for both PTSD and SUD symptomology upon intake.