- Smartphone-based, real-time monitoring of suicidal thoughts was feasible for recent suicide attempters from the community as well as for suicidal inpatients
- Participants who had more severe, persistent suicidal thoughts were the most likely to have attempted suicide within the past month
- Clinicians should assess the average severity of patients' suicidal thinking and the variability around that average
- People with a history of severe and stable suicidal thinking may be at greater risk of engaging in suicidal behavior, but longer-term studies are needed to test that idea
Thanks to advances in smartphone-based, real-time monitoring, it is possible to have individuals report on suicidal thoughts as they occur naturally outside of the clinical setting. Two recent studies that used such technology found that thoughts of suicide can vary considerably over short periods of time, even from hour to hour.
Jeff C. Huffman, MD, clinical director and associate chief of the Department of Psychiatry, and researcher Matthew K. Nock, PhD, and colleagues have become the first to demonstrate that there are phenotypes of suicidal thinking. By collecting several weeks of data, they identified five distinct patterns of suicidal thoughts, which may have implications for predicting suicidal behavior.
As the researchers report in Depression and Anxiety, they advertised a study, in self-harm and suicide forums on Reddit, for adults who had attempted suicide in the past year with at least some intent to die and owned a smartphone. Of 854 people who completed a screening questionnaire, 103 qualified for the study and 90 expressed interest.
The participants completed brief baseline questionnaires and then were monitored via smartphone for 28 days. Four times each day at random times during waking hours they were asked to report on a scale of zero to four:
- How intense is your desire to kill yourself right now?
- How strong is your intention to kill yourself by suicide right now?
- How strong is your ability to resist the urge to kill yourself right now?
Participants were paid $40 plus a $10 bonus if they completed more than 75% of the prompts.
The researchers analyzed data on 51 participants who completed at least three consecutive time points. The average age was 24 years (age range, 18–38), 79% were female and 73% were white. The average number of responses was 2.2 per participant per day, representing a 55% response rate.
Five patterns of suicidal thinking emerged. The principal differences between them were the intensity of suicidal thoughts (average severity over time) and the variability (magnitude of within-person variability around the average).
The group of participants with the most severe and persistent suicidal thoughts was significantly more likely than other groups to have attempted suicide within the past month. In the group whose thoughts were severe but more variable over time, no members had attempted suicide over the previous month.
The researchers set out to replicate their findings in 32 adults who were hospitalized at Mass General following a suicide attempt or severe suicidal thoughts. In this sample, the average age was 43 years (age range, 23–68), 43% were male and 81% were white. The participants were prompted via smartphone four times daily throughout their stay (average nine days, range 2–46) and were paid $10 for each day in the study.
The response rate and findings were similar to those in the community sample, except that the group with severe, persistent suicidal thoughts was not significantly more likely than others to have attempted suicide recently. The researchers speculate that the higher acuity of the inpatient sample may have resulted in a ceiling effect to detect between-group differences in recency of suicide attempts.
The researchers caution that these short studies do not prove that any particular pattern of suicidal thoughts predicts suicidal behavior. Rather, the findings demonstrate that real-time monitoring of suicidal individuals would be feasible in longer-term studies of how to predict and prevent suicide attempts.
For now, according to the research team, the findings do suggest the importance of assessing not just the average severity of patients' suicidal thinking, but also the variability around that average.
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