Selected literature review; November 2022
Suicide is a public health crisis in Canada. More than 4,000 people die by suicide in this country every year, equivalent to a rate of 12.1 per 100,000 or 0.00242 suicides in 20. (This number is derived through a multi-step process; for more information, see our article The accuracy and reliability of suicide statistics: Why it matters.)
How many more people considered suicide, or are living with thoughts of suicide (suicidal ideation)?
A commonly cited ratio is 1 in 20, or 5% of a population, experienced suicide ideation in the past year. While this ratio holds for Canada and other western nations, suicide is impacted by cultural (among myriad) factors; it is not a universally accurate representation. However, it is a useful figure to give us an idea of how prevalent suicidal ideation is in our society and how longstanding the research is behind this ratio. Studies going back to the 1970s bear this out.
What follows is a selection of research papers and government publications which approximate and confirm this ratio for the general population.
Substance Abuse and Mental Health Services Administration. (2021). Key substance use and mental health indicators in the United States: Results from the 2020 National Survey on Drug Use and Health. https://www.samhsa.gov/data/sites/default/files/reports/rpt35319/2020NSDUHFFR102121.htm
Conducted annually by the Substance Abuse and Mental Health Services Administration, the National Survey on Drug Use and Health provides nationally representative data on mental health issues, as well as other measures. In 2020, 4.9% (or 12.2 million people) of Americans aged 18 or older reported having serious thoughts of suicide in the past 12 months. Rates were highest among adults aged 18 to 25 (11.3%, or 3.8 million), followed by those aged 26 to 39 (5.3%, 5.3 million), then by those aged 50 or older (2.7%, 3.1 million). Among those who had serious thoughts of suicide in the past 12 months aged 18 or older in 2020, 21.1% (2.5 million) reported that these thoughts were due to the COVID-19 pandemic. 12% (3 million) of adolescents aged 12 to 17 in 2020 reported having serious thoughts of suicide in the past twelve months.
Statistics Canada. (2020). Canadian Community Health Survey, 2019. https://www150.statcan.gc.ca/n1/daily-quotidien/200806/dq200806a-eng.htm
To better understand trends in self-reported mental health before the COVID-19 pandemic, results from the 2019 Canadian Community Health Survey (CCHS) are compared with results from the 2015 CCHS survey as it is the most recent survey with similar mental health data. 2019 CCHS data cover people aged 12 and older living in the 10 provinces. It is important to note that results for First Nations communities excluded people living on reserves, in the territories, and in remote northern regions of provinces.
In 2019, more than 1 in 10 Canadians aged 15 or older (12%, or about 3.7 million people), reported having considered suicide in their lifetime, showing similar rates observed in 2015. Of these people, 23% (or 843,500 people) reported having seriously contemplated suicide in the past 12 months.
Borges, G., Nock, M.K., Haro Abad J.M., Hwang, I., Sampson, N.A., Alonso, J., Andrade, L. H., Angermeyer, M.C., Beautrais, A., Bromet, E., Bruffaerts, R., De Girolamo, G., Florescu, S., Gureje, O., Hu, C., Karam, E. G., Kovess-Masfety, V., Lee, S., Levinson, D., Medina-Mora, M. E., Ormel, J., Posada-Villa, J., Sagar, R., Tomov, T., Uda, H., Williams, D. R., & Kessler, R. C. (2010). Twelve Month Prevalence of and Risk Factors for Suicide Attempts in the WHO Mental Health Surveys. Journal of Clinical Psychiatry, 71(12), 1617-1628. https://doi.org/10.4088/jcp.08m04967blu
Borges et al. utilized data from the World Health Organization World Mental Health Survey, carried out in 10 developed countries and 11 developing countries, to assess the prevalence of past year suicidal behaviours, and identify risk factors for suicide attempts. For developed countries, they found estimates of past-year prevalence of suicide ideation, plans and attempts were 2.0%, 0.6%, and 0.3%, respectively. For developing countries, they found estimates of past-year prevalence of suicide ideation, plans and attempts were 2.1%, 0.7%, and 0.4%, respectively.
Estimates obtained were in the lower end of ranges for each suicidal behaviour and could be the result of two features of the study: use of conservative items for assessment of each suicidal behaviour (e.g., “serious” thoughts of suicide rather than having “thoughts of death”) and use of large representative samples of respondents from general population, rather than smaller, selective samples of people who may be at an increased risk for suicidal behaviours. Overall, Borges and colleagues found that suicide ideation and behaviours occur at similar rates in both developed and developing countries.
Mościcki, E. K. (1989). Epidemiologie surveys as tools for studying suicidal behaviour: A review. Suicide and Life-Threatening Behaviour, 19(1), 131-145. https://doi.org/10.1111/j.1943-278X.1989.tb00372.x
This review summarizes several community surveys measuring the prevalence and correlates of suicidal behaviours among various communities:
- Paykel et al. (1974) conducted an epidemiologic survey of a sample of the New Haven population aged 18 and older (n=720) to investigate prevalence rates of “suicidal feelings” and behaviours. They found lifetime and past-year prevalence rates of suicidal ideation was 2.6% and 1.5%, respectively.
- Schwab, Warheit, and Holzner (1972) aimed to measure social psychiatric impairment and assess northern Florida’s mental health needs and services. They interviewed 1,645 adults and among these participants, found a life-time prevalence rate of suicidal ideation to be 15.9%.
- Vandivort and Locke (1979) utilized data from the Community Mental Health Epidemiology Program that surveyed 3,935 adults aged 18 and over in the early 1970s in Kansas City, Missouri and Washington County, Maryland. The authors considered any response other than “never” as an indication of suicidal ideation and found 1-month prevalence of any suicidal ideation, ranging from “rarely” to “very often” was 5.4%.
- Goldberg (1981) utilized Kansas City and Washington County data of 489 adults aged 18-24 to assess suicidal ideation and its projection of frequency. In this age group, Goldberg found a past-month prevalence rate for suicidal ideation of 9.6% – a considerably higher percentage than other age groups. However, Goldberg did not assess the frequency distribution of responses so the proportion of those who ‘rarely’ thought about suicide is unknown.
- Ramsay and Bagley (1985) conducted a survey in Calgary, Alberta in 1984 and were the first to survey suicidal behaviours specifically and addressed the key distinction between deliberate self-harm without intentions of dying, or “parasuicide,” and a suicide attempt leading to death. For less serious suicidal ideation, lifetime prevalence rates were 37.8% and past-year rates were 6.0%. For parasuicide, lifetime and past-year prevalence rates were 5.9% and 1.3% respectively. However, due to the low response rate (61%), Ramsay and Bagley report that the findings should be interpreted with caution.
- The NIMH Epidemiologic Catchment Area (ECA) Study, which ran from 1980 to 1985, was a multi-wave and multi-site study to measure suicidal behaviours and was one of the largest of its kind. 18,571 participants aged 18 years and older were surveyed in 5 sites: New Haven, Connecticut; Baltimore, Maryland; St. Louis, Missouri; the Piedmont region of North Carolina; and Los Angeles, California. The three sites, Baltimore, the Piedmont region, and Los Angeles, where data on recency of occurrence was collected, showed prevalence rates of combined past-year and past-month estimates of suicidal ideation that ranged from 7.4% in Baltimore and 14.6% in Los Angeles.
Differences in the populations surveyed (i.e., geographic location or region, differences in cultures and beliefs, and sociodemographic composition of the sample) and methodology (i.e., sampling techniques, operationalization of suicidal behaviours, and secular trends and cohort effects), may explain the variation in prevalence rates of suicidal ideation (Mościcki, 1989).