Depression is significantly more common in individuals who experience TBI compared to the general population. In addition:

• About half of people with TBI are affected by depression within the first year after injury and nearly two-thirds are affected within seven years after injury
• Major depressive disorder (MDD) is the most common psychiatric condition experienced by individuals with TBI
• More than half of the people with TBI who are depressed also have significant anxiety.

Detecting depression after TBI is important because depression:

• negatively affects a person’s ability to function in day-to-day life with negative effects on health, productivity, and quality of life
• is associated with a threefold decrease in adherence to medical regimens in patients with chronic illness
• may last 12 months or longer
• may lead to poorer cognitive functioning
• may lead to aggression and anxiety
• may result in greater healthcare use and costs
• may slow brain injury recovery processes
• may increase the risk of suicide while someone is depressed.

The good news is that counseling and medications have been shown to reduce the symptoms of depression and help people return to usual functioning.

Many different factors contribute to depression after TBI, and these vary a great deal from person to person.

Physical changes in the brain due to injury:
Depression may result from injury to the areas of the brain that control emotions. Changes in the levels of certain natural chemicals in the brain, called neurotransmitters, can cause depression.

Emotional response to injury:
Depression can also arise as a person struggles to adjust to temporary or lasting disability, losses or role changes within the family and society.

Factors unrelated to injury:
Some people have a higher risk for depression due to inherited genes, personal or family history, and other influences that were present before the brain injury.

People with TBI often have a number of physical and psychological symptoms that result from the injury, but that also may be signs of depression. In addition to feeling down, sad, blue or hopeless, depression can lead to a number of other symptoms, as described earlier.

Brief, standardized screening tools that take only a couple minutes to administer can be very useful in identifying whether depression is a current problem. For example, a survey called the Patient Health Questionnaire-9 (PHQ-9) can be taken in about 2 minutes.  While a health care provider is needed to make a clinical diagnosis of depression, this screening tool can be taken at home or in a waiting room and can provide an initial indication about whether or not depression might be present.