Abstracts

Rationale: Studies have found a slightly elevated risk for epilepsy among civilians and Veterans with mild traumatic brain injury (mTBI). Epilepsy and mTBI are both associated with complaints of memory problems, and frequently have comorbid mental health comorbidity. We sought to describe the unique contribution of epilepsy to neurobehavioral symptoms, and unique contribution of epilepsy to risk for suicidal ideology/attempt (hereafter suicide-related behavior [SRB]) in Veterans with mTBI. Methods: We identified Veterans with mTBI using the Comprehensive TBI Evaluation (CTBIE; 2007-2015), which includes characteristics of deployment-related TBI, the neurobehavioral symptom inventory (NSI), and NSI impact. We merged CTBIE data with VA health system for Post-9/11 deployed Veterans with epilepsy. VA health system data identified socio-demographic characteristics, medications the year prior to CTBIE, and conditions common in Veterans (e.g., SRB, PTSD, depression, anxiety, bipolar disorder, insomnia, and substance use disorder) prior to CTBIE.The NSI is a self-reported measure that includes information about how much the respondent was disturbed by 22 symptoms (e.g., depressed mood, dizziness, pain, slow thinking) over the past 2 weeks. Response options range from 0, representing that a symptom is rarely/never present and that it is not a problem, to 4, indicating a very severe problem, one that is almost always present, has interfered with the respondent’s performance at work, school, or home, and that they feel they could probably not function without help. We compiled the 4-dimension subscales of the NSI-22: vestibular, somatosensory, cognitive, and affective, and a separate item that rates the impact of these symptoms using the same 0-4 scale. We compared NSI scale scores by epilepsy and gender strata using general linear models and used logistic regression to examine the extent to which epilepsy contributed to SRB the year after the CTBIE after controlling for comorbid conditions, NSI symptoms, and medications. Results: Among the 88,613 individuals with mTBI and who completed the CTBIE through 2015, 1630 men and 117 women met epilepsy criteria. Women and men with epilepsy had significantly higher scores on all four NSI scales than their non-epilepsy counterparts. Women with epilepsy (WWE) also had significantly higher scores on all NSI scales and NSI impact than men with epilepsy (MWE), whereas the only scale with a meaningful difference between women and men without epilepsy was the vestibular scale where women had significantly higher symptomology (all p<0.01). Logistic regression analysis found that even after controlling for prior SRB, prior overdose and prior mental health diagnoses, MWE and WWE had significantly higher odds of SRB (adjusted odds ratio (AOR) 1.94; 95% confidence interval (CI) 1.60-2.36 and AOR 2.56; 95% CI 1.44-4.57 respectively) the year following CTBIE than their non-epilepsy counterparts. Other significant predictors of SRB included high NSI cognitive and affective symptomology scores, additional TBI following combat deployment, and AED prescription the year prior to CTBIE. Conclusions: This study demonstrated the unique contribution of epilepsy on health outcomes including symptomology that is also independently associated with SRB. While affective symptoms were associated with SRB, cognitive symptoms and perceptions of severe/very severe impact of these symptoms on the social, emotional, and physical functioning were strongly associated with both epilepsy and SRB. These findings support the AAN epilepsy measure set which recommends regular screening for mental health symptoms and quality of life to enhance health and mitigate adverse outcomes. Funding: Department of Defense Congressionally Mandated Research Programs, Epilepsy Research Program, W81XWH-16-2-0046