Using CCTVs, video in the fight against suicide

Closed-circuit television (CCTV) and video systems have seen growing use in the prevention of suicide, particularly for the early detection of preattempts, according to a new study.

“We describe several challenges and considerations which are required to extend computer vision techniques to different settings,” the researchers said. “Ultimately, this research aims to automatically detect behaviours which may be indicative of a suicide attempt, allowing earlier intervention to save lives.”

To conduct a narrative synthesis, the researchers searched through the databases of PubMed, Inspec, and Web of Science, looking for studies that used CCTV or video footage to either understand or prevent suicide. Investigations were included regardless of the methodological quality, as the primary objective of the current review was not to generate quantitative estimates. Nevertheless, shortcomings in design and analyses were taken note of.

Thirty articles were eventually deemed eligible for the synthesis, and a content analysis identified three main ways CCTV and video systems were used in suicide intervention: to understand risk factors, such as inferring depression from facial expressions (n=6); to understand suicide after an attempt, as used in forensics (n=8); and to intervene, using computer vision and automated systems to detect an attempt in progress (n=16). [JMIR Ment Health 2021;8:e27663]

In general, there were two main ways by which CCTVs and video were used to assess suicide risk factor. The first was in the analysis of videos of people who had died by suicide, taking into consideration the means of self-harm, as well as interpersonal relationships, stress, and mental health disorders. The second main approach was to use human and computer vision to infer depression from facial cues.

In forensics, CCTVs have been used to better understand suicide after an attempt, particularly to elucidate the sequence of bodily reactions starting from the attempt up to the eventual death. Notably, two studies pointed out the importance of video footage in accurately determining the cause of death.

In one case, for example, an individual had died by stab wounds to the neck, and the death had been ruled as homicide. But because CCTV footage was available, it was made clear that suicide was the true cause of mortality.

Finally, the most common use of CCTV and video systems in suicide was for the early detection of attempts and potential prevention.

In general, the approach uses video monitoring, with or without an automated alert system to authorities, to either deter or detect red-flag behaviours. Some studies, for example, have noted that just the mere presence of CCTVs have discouraged suicide; others have established that video systems may enable fewer staff to monitor more at-risk individuals, particularly in hospital settings.

Moreover, CCTVs and video also allow for automatic or semiautomatic monitoring, employing sensors that can send alerts to authorities once they detect people climbing through safety railings or entering restricted and unsafe areas, and even those in the middle of a suicide attempt.

“However, even when using automated systems, the ability to intervene is limited to when an attempt is made or a very short period prior to an event, such as entering an unsafe location,” the researchers said, noting that next research steps should look to detect wider windows prior to an attempt, giving the appropriate professionals more time to intervene.

“By investigating predictive behaviours, a third party may be able to intervene earlier or more quickly, which could greatly reduce the incidence of suicide,” they added.