Like the name implies, a traumatic brain injury is extremely serious. But the damage can be just the start of long-term health problems. After a person experiences a traumatic brain injury (TBI), like a concussion from a sports injury, there's an increased chance that a person will also experience depression.
In fact, it's estimated that nearly half of people with a traumatic brain injury will develop depression within the first year. This is alarming given that 1.5 million Americans experience such an injury every year, with 230,000 people requiring hospitalization. Despite being common, the mental health effects can hinder a person's recovery and be difficult to treat. Up until now, doctors have treated this kind of depression with antidepressants and cognitive behavioral interventions. Frustratingly, these interventions don't always work.
"We've been thinking that maybe rather than using psychological or chemical treatments, we should be using structurally-oriented treatments," Dr. Shan Siddiqi, an assistant professor of psychiatry at Harvard Medical School, told Salon. "We have some preliminary data showing that structurally-oriented treatments, specifically targeted brain stimulation treatments, seem to work for these people, unlike the other medical treatments."
"We have believed for a long time that TBI after depression is somehow different, but we have never proven it."
Siddiqi's latest research, published this month in the journal Science Translational Medicine, suggests that the kind of depression that occurs after a traumatic brain injury is different from other types of depression. In the study, researchers propose the new subtype named "TBI affective syndrome." The research adds more evidence to the belief that some psychologists, neurologists and psychiatrists have long held, but have found it difficult to scientifically prove: that there are many subtypes of depression. This new study could contribute to changing the way the mental health condition is treated in the future.
"We have believed for a long time that TBI after depression is somehow different, but we have never proven it," Siddiqi said, adding that there are a few reasons why it's been difficult for scientists to definitively demonstrate, such as limited technology. "What we had to do was identify clusters of symptoms that go together, and then see if they predict treatment outcomes. And it didn't work. It turns out that symptom clustering alone is not good enough."
Instead, Siddiqi said experts needed a "biological filter." Thanks to updated imaging technology, he might have found just that, as detailed in the new study. Specifically, Siddiqi and his colleagues looked at brain scans from people with depression after a TBI, people who had depression without a TBI, and brain scans of people with and without post-traumatic stress disorder.
The researchers found that brain circuits associated with depression were activated in both people who had the mental health condition with and without a TBI. But by comparing the images, it became clear that the ways in which these circuits operated were different. The new imaging technique specifically looked at how oxygen is moving in the brain, providing scientists with detailed maps of the brains of 273 adults with traumatic brain injuries.
"The reason why the different way is important is because it tells us there's a different entity happening, a different disease process," Siddiqi explained. "With people with traditional major depression, these circuits are under-connected, there's less connectivity in the circuits, and after a brain injury, there seems to be increased connectivity of these circuits."
While that might sound like a positive change, Siddiqi said that's not the case.
"Our study doesn't prove exactly what is wrong with them," Siddiqi said. "It might be that they're trying to compensate for something and that's why they go in the opposite direction — or it might be that they're trying to work harder. There are a lot of possible explanations for which we're not sure about, but what we can say is that they're affected in different ways, suggesting there's a different disease process going on."
In June, scientists at Stanford Medicine conducted a study published in the journal JAMA Network Open, also proposing a new category of depression, called the cognitive biotype, estimating that it accounts for 27 percent of depressed patients and that it is not effectively treated by antidepressants.
"Our findings suggest the presence of a cognitive biotype of depression with distinct neural correlates, and a functional clinical profile that responds poorly to standard antidepressants and instead may benefit from therapies specifically targeting cognitive dysfunction," the authors concluded.
"One of the big challenges is to find a new way to address what is currently a trial-and-error process so that more people can get better sooner," said Leanne Williams, the study's senior author in a press statement. "Bringing in these objective cognitive measures like imaging will make sure we're not using the same treatment on every patient."
Dr. Carla Marie Manly, a clinical psychologist and author of "Joy From Fear," who was not involved in either of the studies, told Salon via email that there is no "one size fits all" cure for depression.
"People often make the significant error of clumping all cases of depression into one category, but depression is heterogeneous," Manly said. "Research continues to reveal what clinicians have long suspected: depression has many different root causes and manifests differently in each person."
As a psychologist, Manly said it's exciting that science is providing a "personalized approach" to addressing depression, and said she believes it will help support better treatments.
"Current research is homing in on subtypes of depression; this approach will support treatments that are fine-tuned to the actual root causes of the depression," she said. "The target-practice approach to treating depression and other mental health disorders leaves clients frustrated and feeling broken due to the high rates of ineffective treatment and remission."
Manly added she wasn't surprised by the study that showed depression after a traumatic injury is different. Siddiqi said he hopes that at the very least, his latest study helps destigmatize depression after a traumatic brain injury.
"Since we found this, I've been telling my own patients about it, and they feel a little bit reassured by the fact that there is actually some sort of structural association of what they're feeling," Siddiqi said. "Now that we've localized the dysfunction, it'll be a lot easier for us to figure out how to tailor that treatment."
