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Advanced Neurology TBI and depression by veteran status

severe based on clinical presentations, which at times are also contribute to higher prevalence of depression among
non-specific and non-predictive of future disease course. veterans. 16
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Nevertheless, TBI is the principal cause of mortality Previous studies have identified a relationship between
and morbidity among people under the age of 45 years the incidence of TBI and diagnosis of subsequent mental
globally. Despite major advancements in TBI treatment health disorders among the general population. For this
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and long-term management, a significant number of research, we are focusing our attention solely to TBI and
people still suffer from long-term sequelae. According depression. There remains limited research examining
to prior research, in 2014 alone, the United States (U.S.) this association among veterans, especially using a large
documented 2.53 million emergency department visits due nationally representative U.S. sample. Therefore, in our
to some form of TBI along with 288,000 hospitalizations present study, we analyze the association between TBI and
and 56,800 subsequent deaths. TBI is cited as one of the depression, stratifying this relationship by veteran status.
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most common injuries with lifetime prevalence of 22%
across a population. It is important to note that not all 2. Materials and methods
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cases of TBIs are formally diagnosed in the hospital setting.
This number excludes military veterans who are thought to 2.1. Data source
be at an elevated risk of suffering from TBI. We retrieved data of 29522 participants from the National
There is support that psychological symptoms Health Interview Survey (NHIS) administered by the
associated with TBI, such as depression and anxiety, are Centers for Disease Control and Prevention (CDC)
alleviated within 12 weeks of injury. Recently, researchers National Center for Health Statistics in 2023. Starting in
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have been discussing about a more transient nature of 1957, the NHIS is one of the largest datasets in the U.S.
depression following acute injury that re-emerges as a that annually collects data on a broad range of health
chronic medical condition later in life. In line with recent topics across the country using a geographically clustered
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thoughts, new evidence illustrated that approximately 25 sampling technique through face-to-face interviews with
– 50% of people suffer from depression of varying severity non-institutionalized civilians.
within 1 year of a TBI, 60% within the first 7 years, and
the heightened risk persists even after 50 years of the 2.2. Depression
initial injury. In another study, researchers recorded a The dependent variable was depression, measured using the
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40% prevalence of depression along with a 7.5 relative risk two-item patient health questionnaire (PHQ-2), a subset
among participants, irrespective of TBI severity. 9 of the larger PHQ-8 scale used to screen for depression.
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In a previously conducted study, it was demonstrated Participants were asked during the past 2 weeks whether
that veterans are 31% more likely to suffer from major they have been bothered by the following problems – “little
depression at any point in their life, which is significantly interest or pleasure in doing things” and “feeling down,
higher than the general population. In a subsequent depressed, or hopeless.” Scores ranged from 0 (“not at all”) to
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study, increased frequency of depressive episodes among 3 (nearly every day). Based on scores, results are categorized
veterans was also linked to higher rates of suicide. This is as either “positive” or “negative,” with a score of 3 or higher
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compounded by the fact that veterans usually have worse being identified as “positive” for depression screening.
health outcomes compared to the general population. Despite the shorter scale, the diagnostic performance is
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Veterans who were deployed overseas were twice more comparable to longer scales. The PHQ-2 has been previously
likely to get diagnosed with depression compared to tested to have a sensitivity of 87% and a specificity of 78%
others. While veterans have a higher odds of suffering life for major depressive disorder. 18
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threatening injuries, previous studies indicate that, just like 2.3. TBI history
the general population, most of the brain injuries suffered
by veterans are mild in nature. Another interesting The independent variable was a history of TBI. Participants
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aspect is the assumption that mode of injury might be an were asked, “In your lifetime, have you ever had a significant
important indicator of higher prevalence of depression head injury or concussion?.” This question was asked to
among military veterans. In a recent study, researchers only adults 18 years and older who did not experience any
found that veterans with blast or non-blast injuries had loss of consciousness or head injury symptoms within the
quite similar post-traumatic outcomes. This highlights the past 12 months. Responses were either “yes” or “no.”
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complex causal mechanism of depression among veterans.
While frequent TBI contributes significantly to depression, 2.4. Veteran status
other factors such as living away from family, multiple Sample adults aged 18 and older were asked if they had
combat missions, job stress, and cultural differences might ever served on active duty in the U.S. Armed Forces,

Volume 4 Issue 3 (2025) 71 doi: 10.36922/AN025050008