Major depressive disorder is markedly prevalent in patients with traumatic brain injury, developing in half of patients during the year after their injury.
This rate is nearly 8 times higher than that in the general population, and considerably higher than rates of 12% to 42% reported in previous high-quality studies, reported Charles H. Bombardier, Ph.D., and his associates at the University of Washington and Harborview Medical Center, Seattle.
The study enrolled consecutive patients admitted with complicated mild to severe TBI to a level 1 trauma center in 2001–2005. Most of the participants were men who had been injured in vehicular crashes and had sustained complicated mild injuries. Subjects were assessed using the Patient Health Questionnaire (PHQ) depression and anxiety modules at baseline, monthly for 6 months, and bimonthly thereafter for 1 year. At 12 months, they were assessed using the European Quality of Life measure.
A total of 297 patients (53%) met criteria for MDD at some time during that interval (7% in the general population). This also is higher than the rates reported in previous studies of TBI, perhaps because frequent assessments were conducted, and the investigators were able to capture the cases with transient (1-month) major depressive episodes.
In addition, the sample was characterized by high rates of depression-related risk factors such as alcohol dependence and other preinjury mental health diagnoses, Dr. Bombardier and his colleagues said (JAMA 2010;303:1938–45).
The median duration of depression was 4 months. There was no difference in the rate of depression between patients with mild TBI and those with severe TBI.
About half of the patients who developed depression did so within 3 months of their injury. This finding challenges the idea that poor awareness of impairment precludes depressive reactions during the first 6 months after injury. It also suggests that clinicians should act quickly to identify and treat depression, or even to prevent it.
About 16% of the subjects were depressed when they sustained the traumatic injury; another 27% had a history of depression but weren't depressed when injured. The investigators said the study results might not be generalizable because it was conducted at a single level 1 trauma center in the northwest region of the United States.
The National Center for Medical Rehabilitation Research and the National Institutes of Health supported the study. Dr. Bombardier owns stock in Pfizer Inc.