Trauma Increases Psychiatric Disorder Risk, Independent of Familial Factors

Exposure to potentially traumatic events is associated with an elevated long-term risk for psychiatric disorders, according to study results published in JAMA Psychiatry. This increased risk was not significantly influenced by familial factors and is highest in the first year following a traumatic event. These results suggest a need for rapid clinical monitoring and mental health support following trauma exposure.

While traumatic events frequently precipitate psychiatric disorders, previous studies exploring trauma exposure and the risk for psychiatric disorders are often limited to a particular type of trauma and do not account for potential genetic contributions to this interplay. To this aim, investigators characterized the contribution of familial factors to the long-term incidence trajectories of psychiatric disorders following exposure to potentially traumatic events.

The investigators conducted a cohort study using the Swedish Total Population Register to identify all individuals who resided in Sweden from January 1987 to December 2013, for both population and sibling comparisons. International Classification of Diseases (ICD) codes from the Swedish Patient Register were used to identify individuals’ first recorded exposure to any assaults, injuries, or bereavement and the investigators used Patient Register data to retrieve incident psychiatric disorders following trauma exposure.

A total of 10,191,874 Swedish residents were included in the analyses. The investigators matched each individual exposed to a traumatic event with 10 unexposed individuals based on age, sex, and birthplace. For the population-matched cohort, 49,957 individuals were exposed to assaults, 555,314 were exposed to injuries, and 321,263 were exposed to bereavement. The median age at exposure was 22 years for assault, 19 for injury, and 60 for bereavement. The investigators also established 3 sibling cohorts for assault (exposed: n=34,894; unexposed: n=56,534), injury (exposed: n=388,077; unexposed: n=629,434), and bereavement (exposed: n=191,034; unexposed: n=372,665).

The investigators found that among individuals exposed to traumatic events, the incidence rate (per 1000 person-years) of any psychiatric disorder was 38.1 for assault, 13.9 for injury, and 9.0 for bereavement. Notably, the incidence was highest in the first year following trauma exposure for assault (hazard ratio [HR], 4.55; 95% CI, 4.34-4.77), injury (HR, 3.31; 95% CI, 3.23-3.38), and bereavement (HR, 2.81; 95% CI, 2.72-2.91). After the first year, these values declined to 2.50 (95% CI, 2.43-2.56), 1.69 (95% CI, 1.68-1.70), and 1.42 (95% CI, 1.40-1.44), respectively.

Sibling comparisons revealed a similar trend, as trauma exposure of any type was associated with an increased rate of psychiatric disorders, independent of familial factors. The HRs were highest in the first year following exposure to assault (3.70; 95% CI, 3.37-4.05), injury (2.98; 95% CI, 2.85-3.12), and bereavement (2.72; 95% CI, 2.54-2.91), but were still elevated even after the first year (assault: 1.93; 95% CI, 1.84-2.02; injury: 1.51; 95% CI, 1.48-1.53; bereavement: 1.35; 95% CI, 1.31-1.38).

The findings indicate that exposure to potentially traumatic events is associated with an increased risk for psychiatric disorders that is independent of familial factors. Study authors concluded, “The greatest risk increase observed immediately after the events motivates enhanced clinical alertness of vulnerable individuals during this crucial time window.”
The major study limitation is the reliance on data from only hospital settings or specialized psychiatric clinics, leading to an underestimation of psychiatric disorders due to the lack of primary care data and a greater focus on more severe traumatic events and psychiatric disorders.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of author disclosures.  

This article originally appeared on Psychiatry Advisor