Approximately one in five people who sustain a mild traumatic brain injury (mTBI) will experience symptoms of mental health disorders within 6 months, according to a new study published in the journal JAMA Psychiatry.

The findings suggest the importance of follow-up care for these patients.

The researchers also identified factors that may increase the risk of developing post-traumatic stress disorder (PTSD) and/or major depressive disorder following mTBI or concussion.

“Mental health disorders after concussion have been studied primarily in military populations, and not much is known about these outcomes in civilians,” said Patrick Bellgowan, Ph.D., National Institute of Neurological Disorders and Stroke (NINDS) program director.

“These results may help guide follow-up care and suggest that doctors may need to pay particular attention to the mental state of patients many months after injury.”

For the study, Murray B. Stein, M.D., M.P.H., professor at the University of California San Diego, and his colleagues evaluated the mental health outcomes in 1,155 people who had sustained a mild TBI and had been treated in the emergency department.

At three, six, and 12 months after injury, the participants completed various questionnaires related to PTSD and major depressive disorder. For a comparison group, the team also surveyed individuals who had experienced orthopedic traumatic injuries, such as broken legs, but did not have head injury.

The findings reveal that at three and six months following injury, those who had experienced mTBI were more likely than orthopedic trauma patients to report symptoms of PTSD and/or major depressive disorder.

For example, three months after injury, 20 percent of mTBI patients reported mental health symptoms compared to 8.7 percent of orthopedic trauma patients. At six months after injury, mental health symptoms were reported by 21.2 percent of TBI patients, compared to 12.1 percent of orthopedic trauma patients.

The researchers also used the data to identify risk factors for PTSD and major depressive disorder after mTBI. They found that lower levels of education, self-identifying as African-American, and having a history of mental illness increased risk. Also, if the head injury was the result of an assault or other violent attack, the patient was at greater risk of developing PTSD, but not major depressive disorder.

However, risk of mental health symptoms was not linked to other injury-related occurrences such as duration of loss of consciousness or posttraumatic amnesia.

“Contrary to common assumptions, mild head injuries can cause long-term effects. These findings suggest that follow-up care after head injury, even for mild cases, is crucial, especially for patients showing risk factors for PTSD or depression,” said Stein.

Further research would help identify mental health conditions, other than PTSD and major depressive disorder, that may arise following mTBI. In addition, more work is needed to understand the biological mechanisms that lead from mTBI to mental health problems and other negative outcomes, such as neurological and cognitive issues.

Source: NIH/National Institute of Neurological Disorders and Stroke