And those whose head trauma was followed by depression reported significantly more pain, greater mobility problems and more difficulty carrying out their usual responsibilities than those who were not plagued by post-injury depression.
The 559 participants in this study had all come to a trauma center in the Seattle area with head injuries, signs of brain trauma that could be detected by a CT scan, and at least a few complications — including loss of consciousness or disorientation. Over the next six months, and then again at eight, 10 and 12 months after each participant's injury, researchers conducted a detailed telephone interview to gauge his or her mood and ability to function.
The researchers, from the University of Washington, said the result probably yielded a conservative picture of how many suffered from depression.
David Hovda, a neurobiologist with the UCLA Brain Injury Research Center, said the study made clear what clinicians had long suspected: "Major depressive disorder can have severe consequences for recovery from TBI."
But the study didn't explore some important distinctions, said Hovda, who was not involved in the research. Among those are whether repeated concussions — like those suffered by some U.S. troops and athletes — might make depression more likely than a single, severe brain trauma.
The study included participants whose injuries ranged widely in severity. But the measures that physicians use to diagnose the severity of brain injury were not very good predictors of whether a survivor would go on to suffer depression. The grievously injured had slightly higher rates of depression, yet those thought to have had relatively mild or moderate injuries were nearly as likely as those with the most serious brain traumas to suffer subsequent depression.
Brain-injury survivors who were depressed near or at the time of their accidents, who had suffered post-traumatic stress disorder or had any other past psychiatric diagnosis, and those who were intoxicated on cocaine or methamphetamine, had far higher rates of post-injury depression.
And victims were more likely to report depressive symptoms after their injury if they fit any of the following categories: they were African American, had not completed high school, or their injury was caused by violence (as opposed to a vehicular crash, fall or recreational injury). Also, those who were engaged in litigation associated with their injury were more likely to be depressed (65.5% versus 52.2%) than those who were not.