Evidence map›Paper›PMID 42387492›Full record

ArticleBMC public health2026

Reduction in suicides and suicide attempts following implementation of AI-based video surveillance in the Stockholm metro system: an intervention study.

Johan Fredin-Knutzén, Gergö Hadlaczky, Anna-Lena Andersson, Marcus Sokolowski

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Article in BMC public health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

4 authors.

Johan Fredin-KnutzénNational Centre for Suicide Research and Prevention of Mental Ill-Health (NASP), Karolinska Institutet, Stockholm, S-171 77, Sweden. johan.fredin.2@ki.se.ORCID 0000-0002-9146-9343
Gergö HadlaczkyNational Centre for Suicide Research and Prevention of Mental Ill-Health (NASP), Karolinska Institutet, Stockholm, S-171 77, Sweden.
Anna-Lena AnderssonNational Centre for Suicide Research and Prevention of Mental Ill-Health (NASP), Karolinska Institutet, Stockholm, S-171 77, Sweden.
Marcus SokolowskiNational Centre for Suicide Research and Prevention of Mental Ill-Health (NASP), Karolinska Institutet, Stockholm, S-171 77, Sweden.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundOver 700,000 suicides occurring globally each year are a major public health issue. Railways and metros provide a lethal means of suicide, mainly occurring by persons under train (PUT) events. Restriction of means has been shown to be effective in reducing suicides and is increasingly being prioritized in railway settings, e.g., using physical barriers. Here, we instead investigated the changes in suicidal behavior on metro platforms following the implementation of an AI-based CCTV detection system.

methodsWe used longitudinal data about PUT due to suicidality in the Swedish metro system in Stockholm (2010-2025). A controlled interrupted time series (CITS) analysis, as well as uncontrolled analyses, were used to test if an AI-CCTV implementation in Q4 2021 (at 14 stations) was associated with decreased rates of PUT due to suicidality, compared to the other 86 stations as controls. We also evaluated secondary outcomes (e.g., suicide deaths and train-traffic cancellations). Sensitivity analyses assessed the robustness of the primary model. A separate exploratory analysis examined an extended post-period, which included multiple heterogeneous system-wide exposures.

resultsRates of PUT due to suicidality were lower after AI-CCTV implementation, in analyses with (IRR = 0.27, p < 0.05) or without (IRR = 0.41, p < 0.05) controls. Secondary outcomes showed consistent point estimates, e.g. death by suicide after PUT (IRR = 0.3), safeguarded individuals (IRR = 0.8) and less cancelled train-kilometers in the metro system. The robustness of the changes in PUT and death by suicide outcomes were confirmed by Bayesian sensitivity analyses using weak priors.

conclusionsImplementation of AI-CCTV as described herein was associated with lower rates of PUT due to suicidality at metro stations, as well as changes in the same direction for e.g. deaths by suicide and less cancelled train-kilometers. This preliminary study of AI-CCTV in the metro system provides a specific example of how such an intervention may support suicide prevention in the metro system, at least in the short-term.

Indexed as

Artificial IntelligencePopulation SurveillanceRailroadsSuicideSuicide, AttemptedSuicide PreventionVideo RecordingHumansIntelligent SystemsInterrupted Time Series AnalysisLongitudinal StudiesSwedenArtificial Intelligence (AI)Closed-circuit television (CCTV)MetroRailwayStationSubwaySuicide

Identifiers

PMID42387492
PMCPMC13321902

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.