Dr. Amanda Rabinowitz, PhD, Director of the Brain Injury Neuropsychology Laboratory at the Moss Rehabilitation Research Institute has received a $93,000 grant from the National Institute of Health to learn more about depression in people who have sustained traumatic brain injury (TBI). Specifically, she and her team are hoping to understand whether depression or a lack of participation in one's usual activities comes first–what Dr. Rabinowitz refers to as a "chicken-or-the-egg" problem.

"We know that people with TBI may not be able to participate in their regular activities and experience the sense of reward that comes from them," says Dr. Rabinowitz. "And this may lead to depression. However, people who become depressed first may also disengage from their usual activities. So our question is which one of the mechanisms is causing the other?"

She adds that her sense is that it's the former relationship that's happening: That people with TBI aren't able to engage and enjoy activities that contribute to mental health and well-being, so they may develop depression as a result. But both phenomena may be going on in different people.

As part of the study, Dr. Rabinowitz will be looking back at rich data from a long-running study, known as the Traumatic Brain Injury Model Systems program– a 20- year collaboration among researchers at 16 institutions around the country– to help illuminate it.

The team will track the participants' involvement in different types of activity over the first two years of their recoveries. One area is One area is "productive activity," which includes household chores and the participant's professional work; another is "out and about," which includes leaving the house to engage in leisure activities or other pursuits, such as volunteering; and the third is "social relationships," and refers to how connected a person is to their spouse, friends, and family. Correlating patterns of engagement to changes in mental health and the onset of depression will help answer the chicken-or-egg question.

The ultimate goal is to fine-tune depression treatment for people with TBI. Behavioral Activation for Depression is one therapy that Dr. Rabinowitz believes holds particular promise for people with TBI, since it involves helping people engage in more rewarding activities. "If someone is depressed, and you can get them to engage more meaningfully in their community, their mood may start to improve. That's the model we're interesting in applying to TBI."

Depression may be common in TBI patients, but recovery is much more dynamic than previously thought. "Changes can happen well beyond the first year after injury," she says. "Models of depression treatment in the general population can be applied to TBI, if we can understand the patterns that are occurring. That's really the important implication in this research."

Dr. Rabinowitz's past research has looked at how people who have sustained moderate to severe TBI recover over time, and how their symptoms wax and wane, and she has found Depression is one of the more common occurrences among TBI patients.

"Understanding more about its (depression in TBI patients) etiology is important," said Dr. Rabinowitz. "It can lead to more personalized treatments."