Late-night phone surfing has been linked to an increase in suicidal thoughts

A new study has found: in adults at high risk of suicide, late phone activity between 23:00 and 01:00 correlates with more suicidal thoughts and planning for the next day.

The work, which is published in the journal JAMA Network Open, involved 79 adults who had recently reported suicidal thoughts or behaviour. For 28 days, they had an app installed on their smartphones that took a screenshot every 5 seconds while the screen was active. In total, the researchers collected more than 7.5 million images. In parallel, the so-called Ecological Momentary Assessment (EMA) was conducted - the participants reported their state and thoughts in real time several times a day.

Using a deep learning model, the scientists divided nighttime smartphone use into "passive" (scrolling through content without a keyboard on the screen) and "active" (with a keyboard - texting, typing, etc.). The analysis showed that longer intervals of phone use at night - 7-9 hours in a row - were associated with lower levels of suicidal thoughts the next day compared to intervals of 4-7 hours.

The evening and nighttime period attracted particular attention. Smartphone activity between 23:00 and 01:00 was associated with higher levels of suicidal planning the following day, compared to using the phone later - between 01:00 and 05:00 - or in the early morning. Conversely, active phone use with typing (on-screen keyboard) between 01:00 and 05:00 was found to be associated with slightly lower risk the following day. The authors suggest that the person may then be in contact with others (texting, asking for support), which partially reduces risk, although no direct causal conclusions can be drawn.

The study fits into the broader context of evidence that poor sleep quality and sleep deficits increase suicidal ideation. Nighttime smartphone use may further disrupt sleep due to blue light, emotionally charged content and nighttime notifications. It has previously been noted that people with suicidal ideation are more likely to 'linger' on their phones, but less was known about exactly how nighttime digital activity relates to risk the next day and whether the nature of use - passive scrolling or active socialising - plays a role.

Experts commenting on the paper urge caution about the results: the sample is relatively small, the study was conducted in a single centre, and the participants themselves may have different perceptions and assessments of their activity. At the same time, the authors believe that the discovered patterns may help to develop more targeted approaches to suicide prevention in the future, such as digital monitoring systems and timely interventions that take into account specific patterns of nighttime smartphone use in people at risk.