Mild Traumatic Brain Injuries Linked to Depression-Like Side Effects: Study

Researchers found that even minor head injuries may affect the system that controls neurotransmitters in the brain.

A new study suggests that suffering even a mild traumatic brain injury (TBI) increases the likelihood a person will begin withdrawing from social relationships and spending less time on self-care, highlighting the risks associated with any head injury.

TBIs occur when a person suffers a blow to the head, which can come from severe impacts like those seen in car accidents and sports injuries, or from a mild impact, often known as a concussion.

Prior research has indicated suffering a severe head injury can lead to chronic changes in brain function, thinking, memory and emotional symptoms. These types of head injuries can also increase the risk of serious side effects, including long-term headaches, increased risk of stroke, dementia and early death.

According to new animal research published in the November 2024 issue of the medical journal Neuroscience, researchers indicate that even individuals who suffer minor head injuries may experience symptoms of depression, potentially leading to detrimental changes in their social and personal lives.

TBI Depression Risks

In this new study, a team of researchers led by Pamela VandeVord at Virginia Tech explored the effects of mild traumatic brain injury (mTBI) on depression by inducing these injuries in mice and rabbits, and then examining the resulting impacts at intervals of four, eight and 12 weeks.

According to the findings, animals that experienced minor brain injuries showed a decreased preference for social interaction by 12 weeks. When given opportunities to be social, isolated or in between, animals that suffered head injuries spent more time alone at eight weeks than animals that did not suffer head injuries. They also showed a decreased preference for new social situations as early as four weeks.

The researchers noted that while this study looked at the effects on animals, the outcomes translate to human head injuries and side effects as well. People who suffer even a minor head trauma often experience a similar loss of desire for social interaction and loss of interest in self-care, according to the study.

VandeVord’s team detected changes to the glutamatergic system when TBIs occurred, with elevated levels of some glutamate chemicals in the brain and chronic drops in others. The glutamatergic system is known to affect neurotransmission throughout the brain, but the team concluded more research is needed into how the system functions and how it relates to depression in the brain, especially following injuries to the head.

“Together, these results suggest that the development of chronic depression-like behavior was associated with changes in glutamatergic protein expression,” VandeVord’s team concluded. “Deeper investigations into how injury influences glutamatergic synaptic protein expression are needed, as this has the potential to affect circuit-level neurotransmission that drives depression-like behavior following mTBI.”

A recent Harvard study also linked TBIs to an increased likelihood of suffering a type of depression that is resistant to standard treatments, like antidepressants and therapy. That study, along with the findings of the new research, add to a growing body of evidence linking concussions and head injuries to a heightened risk of depression and symptoms related to depression.