Traumatic Head Injury and Long Term Risk of Depression
Of particular concern to care providers evaluating and treating patients injured in auto accidents is the possibility of head injury. Most individuals who sustain a traumatic head injury diagnosed as a mild concussion will experience no sequelae beyond nine months after the injury incident. That is not always the case however. A study recently published in Archives of General Psychiatry contains significant findings on the incidence of long term depression experienced by men who sustained a head injury in their late teens to early twenties.*
The study was done of World War II veterans with documented cases of wartime hospitalization for head injury, pneumonia, laceration, puncture, or incision wounds. Almost all cases of injury occurred between 1943 to 1945. From 1996 to 1997, 520 subjects with head injuries and 1198 without head injuries were interviewed to obtain their lifelong history of depressive illness. Cases of dementia were excluded.
Military medical records were abstracted for documented evidence of brain trauma. Criteria included:
- Occurrence during military duty;
- Loss of consciousness, post-traumatic amnesia, or non-depressed skull fracture;
- No penetration of the dura; and
- No significant cognitive impairment more than three months post-injury (significant impairment defined as substantial limitation of activities of daily living). After review of the medical records, the head injuries the men sustained were rated for severity into the categories of:
- “mild” (loss of consciousness or post-traumatic amnesia for less than 30 minutes);
- “moderate” (loss of consciousness or amnesia for more than 30 minutes but less than 24 hours); and,
- “severe” (more than 24 hours of loss of consciousness or amnesia.)
The head injured individuals and/or their family members were interviewed regarding any lifetime history of depression. Those with positive responses were then administered a modified version of the “Diagnostic Interview Schedule” section on depression. Further questioning and exclusion was made on the basis of history of alcohol abuse or dementia.
The statistical results showed a significant link between traumatic head injury and later depression. The veterans with head injuries reported major depression more often, and were more often currently depressed. Employing controls for age and education, the researchers found the head-injured group had an 18.5% rate of major depression as opposed to 13.4% for those wounded veterans with no head injury. 11.2% of the head-injured veterans were experiencing current major depression, as opposed to 8.5% who did not have a head injury. History of alcohol abuse, cerebrovascular accidents, or myocardial infarction played no factor in the increase of the incidence of depression. Incidence of Post Traumatic Stress Disorder among the subjects was not a factor which changed the statistical outcome.
The researchers found a clear association between head injury during early adulthood and a lifetime prevalence of both major and minor depression. While the mechanism involved is unclear, the authors noted other research which suggests injury from coup contra coup lesions, hypoxic-ischemic damage, diffuse microvascular damage, and diffuse axonal damage can occur in head trauma. Other structures and lesions possibly implicated are mentioned. Also unclear is whether depression results from direct brain damage, or as a response to it. Inflammatory response is also noted as a possible mechanism, involving the production of cytokines such as interleukin 6, which has been observed at elevated levels in persons with depression and Alzheimer’s disease.
The authors of this study noted depression shortens one’s life span and degrades oneís quality of life. Our civil justice system recognizes these effects when they are the result of a traumatic personal injury as items of general damages for which those who have sustained them may be compensated. In the medical/legal context, therefore, as well as the treatment context, it is important depression not be overlooked, ignored, or underestimated. Brain injury trauma patients are well advised to seek a consultation with experienced personal injury attorneys who are especially well versed in brain injury conditions and issues such as the attorneys at Adler Giersch PS. Free consultations with the personal injury recovery attorneys of Adler Giersch are available for those with traumatic brain injury throughout Washington State.
Clinicians need to be aware there is an enhanced risk of later depression among head injury patients as identified by this study. Signs of acute or chronic depression should be noted and charted. Obtaining a comprehensive history of remote head injury can also produce evidence with clinical and forensic value in patients presenting with depression, particularly when issues of diagnosis and causation are being contested. Moreover, physicians ought to at a minimum be sufficiently familiar with the issue to address and discuss it in the personal injury medical-legal-insurance areas whether in chart notes, narrative reports, or in testimony at deposition or trial.