A team of researchers from Tel Aviv University has found that smartwatches containing digital biomarkers can detect early signs of PTSD among wearers.
The three-year study — which was carried out both before and after the October 7, 2023, Hamas attack — involved more than 5,000 Israelis, and reported that such devices could sense the onset of post-traumatic stress disorder, even among those only indirectly exposed to traumatic events through the media.
“The percentages of PTSD and anxiety were extremely high among people who were not hurt themselves, or didn’t have a close relative who was hurt” in the Hamas attack, said Prof. Erez Shmueli, head of the Big Data Lab, and Prof. Dan Yamin, head of the Lab for Digital Epidemiology and Health Analytics, both at Tel Aviv’s School of Industrial and Intelligent Systems Engineering, who led the team of researchers in Israel and at Stanford University.
“The GoPro videos that the terrorists shared on TikTok and other platforms actually make you feel the events more closely,” Shmueli told The Times of Israel. “When we looked at the effect of news consumption and watching gory videos, we saw a real difference between people who consumed the news and videos compared to those who didn’t.”
While most PTSD research focuses on people directly exposed to violence, this study examined those indirectly affected through news and social media consumption.
The study, which was published on Wednesday in the peer-reviewed PLOS Mental Health journal, found that smartwatches, combined with questionnaires, can pick up subtle physiological and behavioral changes that foreshadow PTSD, and can help improve public health strategies.
Prof. Erez Shmueli, head of the Big Data Lab at the School of Industrial and Intelligent Systems Engineering at Tel Aviv University (Courtesy)
Stress levels didn’t return to normal
The researchers involved in the study had already been using smartwatches to track participants for another survey, which focused on studying the symptoms and spread of three infectious diseases — COVID-19, influenza and group A streptocococcus (GAS).
These same participants continued in the study, completing a daily questionnaire assessing their stress levels, and wearing a smartwatch that tracked various measures of well-being, such as daily heart rate, number of steps they took and sleep quality.
For Shmueli, one of the most striking results was the persistence of stress long after the devastating Hamas-led attack. The analysis showed that two months after October 7, PTSD rates reached 22.9%-36% among participants, and even months after the attack, the rates remained at 15.9%-24.7% of those surveyed.
“In most other events, we saw an immediate return to routine on average,” Shmueli explained. “After October 7, even a year later, the level of stress was still very high.”
Prof. Dan Yamin, head of the lab for Digital Epidemiology and Health Analytics at Tel Aviv University. (Courtesy/Tel Aviv University)
Social media’s significant impact
“We now live in an era where a lot of our exposure to events is coming from social media,” Shmueli added.
He pointed out that during the September 11 al-Qaeda attacks on the US in 2001 — which killed nearly 3,000 people — social media was not widely used, and rates of PTSD among indirectly-exposed populations were lower.
The study found that 33% of participants who watched extensive amounts of news coverage or graphic videos of the attacks on such platforms as Telegram and TikTok had a higher risk of developing PTSD. Among those who didn’t consume content on those platforms, only 7% exhibited early signs of PTSD.
Hamas terrorists attack the IDF’s Nahal Oz base on October 7, 2023, as seen in footage released by the terror group. (Screenshot: Telegram)
Early warning signs
Clinically, PTSD can only be diagnosed 30 days after a traumatic event. But in the study, participants who later developed PTSD showed distinct changes in the first week after October 7.
Smartwatches and daily questionnaires can provide immediate early markers for PTSD, Shmueli said.
“People who will later be diagnosed with post-trauma tend to have higher self-reported stress levels, they sleep less, the quality of their sleep is lower, and they do fewer steps,” he explained. “Such information, if provided to machine learning and AI models, could help identify people with a higher likelihood of developing PTSD.”
That early identification matters because treatment is most effective when started quickly, he pointed out.
“The earlier you diagnose it, the earlier you can treat it, and the better the results are,” Shmueli said. “You can prevent progression — you can actually, in some way, eliminate the outcome, or at least reduce its effect.”
Illustrative: Family and friends attend the funeral of a reservist soldier who died by suicide after 300 days of reserve duty, at the cemetery in Netanya, August 1, 2025 (Tal Gal/Flash90)
A ‘first line of defense’
Given the strain on Israel’s mental health system, Shmueli sees potential in digital tools for milder cases. “Even if you can identify some portion of people early and treat them — maybe with mobile apps for relieving symptoms — you can leave the health system for the more difficult cases,” he said.
He pointed to PTSD Coach, an app developed by the US Army and Stanford, designed for veterans experiencing symptoms of PTSD. Although it is not a replacement for therapy, Shmueli said it is an example that “actually works pretty well.”
Shmueli believes there is progress in developing this kind of app in Israel so that smartwatches, apps and AI become a “first line of defense,” flagging cases early and easing the burden on healthcare professionals.
These early markers are especially important now, “as we are starting to understand the effect of the events of the war and October 7,” he said.
“The number of people who are turning to the mental health system is huge,” he noted. “Our system has a lot of difficulties in treating all the people who need services.”
While the study highlights limitations, such as reliance on self-reported surveys rather than clinical diagnoses, it underscores how wearable technology could transform mental health care in times of crisis.
“If we can identify and support people as early as possible, it can make a real difference,” Shmueli said.