Rates and predictors of the emergence and remission of suicidal thoughts and behaviors after traumatic brain injury: a Traumatic Brain Injury Model Systems National Database study

OBJECTIVE: To characterize the emergence and remission of suicidal thoughts and behaviors after traumatic brain injury (TBI) over a ten-year period post-injury. METHODS: We analyzed data from 5,540 individuals with moderate-to-severe TBI, who had ≥2 consecutive Patient Health Questionnaire (PHQ)-9 scores across years (Y) 1, 2, 5, and/or 10 post-TBI. We estimated probabilities of the emergence and remission of suicidal thoughts across consecutive follow-up interviews (Y1-Y2, Y2-Y5, Y5-Y10), while accounting for all-cause mortality. We identified associated demographic, pre-injury, and Y1 post-injury factors. Probabilities of emergence and remission of suicidal behaviors were investigated. We explored the competing risk of death by suicide/unintentional poisonings versus all other deaths. RESULTS: Most individuals with suicidal thoughts at a given interview remitted by their subsequent interview (~70% remission from Y1-Y2 and Y2-Y5; 48% Y5-Y10). However, about 6% of individuals developed new suicidal thoughts across interviews. Approximately 30-40% reported chronic thoughts. Risk factors for new suicidal thoughts were pre-injury psychiatric history and post-injury substance use at Y1. Higher functional status and stronger social relationships at Y1 post-injury were protective against the onset of new suicidal thoughts. The majority (70-75%) of persons with suicidal behaviors did not report additional behaviors during subsequent interviews. We found similar rates of death by suicide/unintentional poisoning among individuals with and without prior suicidal thoughts. CONCLUSIONS: Suicidal thoughts and behaviors among those with a history of TBI are dynamic, with notable numbers of individuals reporting new or persistent thoughts. Identifying at-risk individuals and addressing modifiable factors may reduce suicide risk and improve mental health following TBI.