Functional MRI (fMRI) shows variations in how peoples' brains respond to traumatic events -- and that these variations may predict negative long-term mental health outcomes, according to a study published October 14 in the American Journal of Psychiatry.
The study findings suggest that "brain activity profiles" determined in part by fMRI could improve patient care, a team led by Laura Stevens, PhD, of Emory University in Atlanta, GA, found.
"Establishing reliable, predictive profiles of stress response could improve clinical care, helping providers deliver effective interventions that are tailored to trauma survivors' individual needs and circumstances," said the U.S. National Institute of Mental Health (NIMH) in a statement about the research. The institute funded the study that Stevens and colleagues used for their investigation.
Each person's brain responds to stress caused by a traumatic event differently, with some people showing a strong initial reaction that dissipates over time while others experience longer-term stress symptoms that make it hard to fulfill day-to-day activities.
The research is part of the NIMH's Aurora study, which followed more than 3,000 people for up to 12 months after they experienced a traumatic event. Stevens' group selected 68 participants treated in an emergency department after a car accident.
Two weeks after the traumatic event, each person's brain activity was measured using fMRI while they completed a series of computer-based tasks that prompted responses to social threat cues, reward cues, and situations that tested their impulsivity. Study participants also reported over six months via digital surveys any symptoms of post-traumatic stress disorder (PTSD), depression, dissociation, anxiety, and impulsivity.
Study participants were categorized into four "brain profiles":
- Reactive/disinhibited: Strong threat- and reward-related activity and weak response inhibition activity
- Low reward/high threat: Strong threat-related activity and low reward-related activity
- High reward: Strong reward activity, weak response inhibition, and no threat activity
- Inhibited: Little threat, some inhibition, and low reward activity
People with the reactive/disinhibited brain activity profile had more acute symptoms of PTSD and anxiety over six months of follow-up compared with those with other brain activity profiles, the researchers found. There was no link between any of the brain profiles and other outcomes such as depression, dissociation, or impulsivity, the authors noted.
This primary finding shows why some people are more vulnerable to long-term mental effects after trauma, the NIMH said.
"The link between high reward reactivity (as part of the reactive/disinhibited profile) and long-term symptoms was unexpected, as previous studies indicate an association between low reward reactivity and post-trauma PTSD and depression," the institute said. "The researchers suggest that reward reactivity warrants greater attention in future studies as a potential risk factor for stress-related symptoms following trauma."
