Women are more likely to develop depression after suffering a traumatic brain injury (TBI), a new study shows.

The analysis of nine published studies included nearly 700,000 people and found that the risk for depression among women after a TBI was nearly 50% higher than it is for men.

“Depression is a known risk factor for poor recovery after TBI,” said lead researcher Dr. Isaac Freedman, an anesthesiology resident at Massachusetts General Hospital in Boston. “In 2019, suicide was the leading cause of TBI-related deaths. In fact, the average suicide rate was more than six times higher in those who suffered a TBI.”

It’s well-established that there is an association between TBI and depression, but the mechanisms behind this relationship remain unclear, he said.

“One leading theory relates to the critical role of the neurotransmitter glutamate. In the brain, glutamate is one of the most important and wide-ranging neurotransmitters. Glutamate has also been implicated in neuroplasticity — the process by which the brain rearranges its connections and can change over time,” Freedman said.

TBI may cause excess glutamate, which can be toxic to cells and cause cell injury or death. An imbalance in glutamate may be responsible for an increased risk of depression, he suggested.

It is also unclear why depression disproportionately affects women with or without TBI, Freedman said.

“Fluctuations in ovarian hormones are implicated in some causes of related affective disorders, such as premenstrual dysphoric disorder, postpartum depression, and postmenopausal depression and anxiety. However, why women are more often affected by depression is unclear,” he said.

“In older women, the most common cause of TBI is falls, and loneliness and depression are leading causes of death. Therefore, identifying older women who are at risk for depression following head injuries from falls is an important public health target,” Freedman explained. “Physicians should be aware their female patients who suffer head injuries and trauma may be at an increased risk for depression compared to their male patients.”

Specifically, Freedman and his colleagues found that out of more than 360,000 women who suffered a TBI, nearly 106,000 developed depression (29%), compared with more than 72,000 of nearly 331,000 men (22%).

The findings were presented Monday at the annual meeting of the American Society of Anesthesiologists, in San Francisco. Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.

“In some ways, it’s a wake-up call,” said Dr. Robert Dicker, a child and adolescent psychiatrist at Northwell Health Zucker Hillside Hospital in Glen Oaks, N.Y.

“It isn’t a surprise, because the rate of depressive illnesses is higher in women than in men,” Dicker said. “So, whatever population you’re looking at, rates of females with depressive disorders are higher than males. So, this finding just confirms that.”

This study really underlines that doctors need to be paying attention to mood disorders in men and women. “But especially women, and to really be able to pick up whether they’re suffering from depression,” he added.

Dicker thinks that TBIs are underestimated in women. For example, the number of TBIs in women’s soccer is very high, he noted.

“So I wonder if it’s underappreciated in terms of the injury to begin with?” Dicker said. “Does that add to the possibility of them developing a depressive illness?”

Doctors, family members, coaches and others need to be aware of the risk of depression among women after a TBI, he advised.

Dicker said that people suffering from depression don’t have to suffer alone. Treatments are available, including cognitive behavioral therapy and antidepressants.

“The good news is that, over time, the response rates are equal in men and women in treating depressive illness after a TBI, so people don’t have to suffer with this,” he said.

More information

For more on traumatic brain injury, head to the U.S. National Institute of Neurologic Disorders and Stroke.

SOURCES: Isaac Freedman, MD, MPH, anesthesiology resident, Massachusetts General Hospital, Boston; Robert Dicker, MD, child/adolescent psychiatrist, Northwell Health Zucker Hillside Hospital, Glen Oaks, N.Y.; Oct. 16, 2023, presentation, American Society of Anesthesiologists annual meeting, San Francisco, Oct. 16, 2023