AsianScientist (Sept. 17, 2026) – On 11 March, 2011, a magnitude 9.0 earthquake struck the northeastern coast of Japan, triggering a tsunami that damaged several nuclear power plants and created serious risks from radioactive releases. The disaster resulted in deaths, missing persons, injuries, and the displacement of tens of thousands of people.
More than 15 years after the Great East Japan Earthquake (GEJE), the long-term psychological impact of the earthquake, tsunami, and nuclear accident remains a major public health concern.
Long-term post-traumatic stress reactions (PTSRs) are a significant public health concern, but predicting who will develop persistent symptoms remains challenging.
A study by researchers at Tohoku University found that changes in trauma symptoms during the first two years after the GEJE are a better indicator of long-term mental health impacts compared to a single assessment taken shortly after the event.
The results were published in JAMA Network Open.
For the study, the scientists used data from 1,291 residents of Shichigahama, aged 20 years or older, whose homes were damaged or destroyed by the 2011 GEJE and tracked their mental health over 15 years.
Using a statistical method that grouped people according to how their symptoms changed over time, the team identified five different long-term patterns of posttraumatic stress reactions (PTSR).
They found that 14.7% of individuals involved continued to show significant trauma symptoms 15 years after the disaster, demonstrating that psychological effects can linger for more than a decade.
They also found that changes in symptoms during the first two years were far more significant than the initial severity of symptoms following the disaster, which did not effectively predict long-term recovery.
Participants whose symptoms worsened between the first and second year following the disaster were over five times more likely to still experience notable trauma symptoms 15 years later compared to those whose early symptoms did not persist.
This connection remained strong even after taking into account variables such as age, gender, resilience, sleep issues, and the severity of symptoms at the initial assessment.
When the researchers compared various prediction models, those that incorporated changes in symptoms over time were substantially more precise than those relying solely on a single early assessment, highlighting the importance of ongoing follow-up assessments for identifying individuals at risk of long-term psychological distress.
The study also identified early sleep disturbances as a significant risk factor associated with persistent trauma symptoms. As sleep issues are often treatable, they may offer a chance for early intervention that could enhance long-term mental health outcomes.
However, the researchers could not determine how the COVID-19 pandemic and other major stressors from 2021 to 2024 influenced the findings due to the lack of frequent assessments during that time.
“Our findings show that recovery after a disaster is not a fixed process,” said Xue Li, assistant professor at Tohoku University’s Graduate School of Medicine who led the research.
“Monitoring how symptoms change during the first two years provides much clearer insight into who may need long-term support. Continuous follow-up, rather than a single assessment, should become a key part of disaster mental healthcare,” she added.
“Our findings suggest that disaster survivors should receive regular mental health check-ups during the years following a disaster, rather than relying on one-time screening,” said Hiroaki Tomita, professor at the Department of Psychiatry, Tohoku University’s Graduate School of Medicine.
“By identifying people whose symptoms worsen over time, healthcare providers may be able to offer support before problems become long-lasting, he added.
These findings carry significant implications for disaster recovery and public health. As specialised disaster mental health services eventually shift back to regular community healthcare, individuals with worsening symptoms could be neglected if support relies only on initial screenings.
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Source: Tohoku University; Image: Maginific
The study can be found at: Posttraumatic Stress Dynamics and 15-Year Persistence in Great East Japan Earthquake Survivors
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