Classification statistics for the suicide attempt gate and follow-up questions.

<p>^a PPV = Positive Predictive Value</p><p>^b NPV = Negative Predictive Value</p><p>Note: Sensitivity is the proportion of actions coded as a true suicide attempt among people that endorsed a suicide attempt on the gate and follow-up questions. Specificity is the proportion of behaviors coded as not being a suicide attempt among people that denied a suicide attempt on the gate and follow-up questions. Positive predictive value is the proportion of people that endorsed a suicide attempt on the gate and follow-up questions among those that were coded as having attempted suicide. Negative predictive value is the proportion of people that denied a suicide attempt on the gate and follow-up questions among those that were coded as not having attempted suicide. Raw values for the proportions are given in parentheses.</p><p>Classification statistics for the suicide attempt gate and follow-up questions.</p

Responses to single-item suicide attempt question and the results of coded narrative responses.

<p>Single-item suicide attempt questions result in a 10.7% false positive rate and 6.39% false negate rate for the sample (9.91% false negative rate among ideators).</p

Characteristics of suicide planning among participants who attempted suicide and either endorsed a single-item plan or did not.

<p>For those that endorsed a single-item lifetime suicide plan (blue) and for those that denied a single-item lifetime suicide plan (red), the distributions of (A) the amount of time between thinking of the method and attempting suicide, (B) the decision to attempt and attempting suicide and (C) thinking of place to attempt suicide and attempting suicide and (D) the percentage of participants that made <i>any</i> preparatory actions and the mean number of preparatory actions prior to a suicide attempt. If participants interpreted a “suicide plan” similarly, one would expect minimal overlap between distributions of planning characteristics for single-item “planners” and “non-planners.” Instead, each of the distributions overlap substantially (71–92%) using the bins in the current plot, suggesting participants do not reliably interpret the single-item suicide planning question.</p

Demographic information.

<p>Demographic information.</p

Responses to gate and follow-up questions for suicide plans.

<p>^a Participants who responded “No response/Not applicable” or left the item blank were excluded resulting in changing totals (i.e., denominators).</p><p>^b Only participants that endorsed or denied all 5 planning components were included. Using the full sample in the denominator (i.e., 176), 10.80% of people who denied a plan, endorsed four or five planning components</p><p>Responses to gate and follow-up questions for suicide plans.</p

Responses to gate and follow-up questions for suicide ideation.

<p>Responses to gate and follow-up questions for suicide ideation.</p

A visual example of DV-misclassification relationships and the results of the statistical simulations.

<p>(A) Model data of a “true effect" (B) Model data of a “true null effect.” The red and green arrows in (A) and (B) represent data points that will be misclassified due to participants inaccurately categorizing their suicidal behavior. (A) and (C) show an example of when the misclassification is random (i.e., dependent variable (DV)-misclassification correlation is zero). Because true attempters tend to be higher on the DV, true attempters randomly misclassified into the non-attempters group will tend to increase the group mean of non-attempters (e.g., from 39.57 in (A) to 42.17 in (C)). Likewise, in the example, true non-attempters tend to be lower on the DV and therefore, true non-attempters randomly misclassified into the attempters group will reduce the group mean of attempters (e.g., from 51.63 (A) to 44.03 in (C)). Thus, when there is a true difference between the groups at the population level, random misclassification will cause the two group means to move closer together reducing the power to detect the true effect. (B) and (D) shows an example of when there is a pattern to the misclassification (the DV-misclassification correlation is approximately <i>r</i> = 0.20). In this example, attempters higher on the DV tend to misclassify their behavior, causing an increase in the mean of non-attempters (e.g., from 43.66 in (B) to 52.56 in (D)). Non-attempters that are lower on the DV tend to misclassify their behavior, causing a decrease in the mean of attempters (e.g., from 43.76 in (B) to 34.83 in (D)). Thus, during a “true null effect” when the DV-misclassification correlation is present, misclassification causes the group means to shift further apart, increasing the probability of finding a false significant difference. (E) The outcome of the statistical simulation for data with a “true effect” across different effect sizes (varying sample sizes to maintain statistical power at 0.95). Without a DV-misclassification correlation, power to detect the true effect is reduced by approximately 15% across all effect sizes. Power decreases as the DV-misclassification correlation strengthens in the opposite direction of the true effect, increasing the chance of a false negative result (i.e., Type II error). This reduction in power is greater when the effect size is small and the sample size is large compared to when there are larger effect sizes and smaller sample sizes. (F) The “true null effect” across the same sample sizes as in the true effect simulation (alpha = 0.05). When misclassification is random for a “true null effect,” it does not affect the false positive error rate. As the DV-misclassification correlation strengthens in either direction, chances of a false positive increase (i.e., Type I error). Compared to larger sample sizes, chance of a false positive is greatest when there is a smaller sample size.</p

A flow chart of the online survey.

<p>Gate questions are single-item questions for three suicidal outcomes. Suicide ideation follow-up questions include eight different thoughts and suicide action follow-up questions include five different actions. Participants that denied any suicidal thoughts or behaviors in the first three sections skipped to the end of the survey. Participants that endorsed any suicidal thought or behavior completed several follow-up questions regarding planning behaviors and narrative descriptions of their behavior.</p

Multivariate model for associations between traumatic events and suicidal behavior¹.

<p>*Significant at the .05 level, two-sided test.</p>1<p>Assessed in Part II sample due to having Part II controls. Some countries were missing part of the trauma variables and were coded “No” for those variables: Combat, Exposure to War, Refugee were all coded “No” for India and Brazil, and Natural Disaster also coded “No” for Brazil. For Israel, the entire sample is coded “Yes” for exposure to war with the age of onset set to the age they moved to Israel. Controls for all models included person-year, country, demographic factors (age, sex, time-varying education, time-varying marriage), interactions between life course (3 dichotomous dummies representing early, middle, and later years in the person's life) and demographic variables, parent psychopathology, and childhood adversities (additional details available upon request).</p

Association between traumatic events and persistence of suicidal behavior¹.

<p>*Significant at the 0.05 level, 2-sided test.</p>1<p>Assessed in Part II sample due to having Part II controls. Countries include: Belgium, Brazil, Bulgaria, Colombia, France, Germany, India, Israel, Italy, Japan, Lebanon, Mexico, Netherlands, New Zealand, Nigeria, People's Republic of China, Romania, South Africa, Spain, Ukraine, United States. Results are based on discrete time survival model with country differences, a set of age-related variables (i.e., age, onset and time since onset), sociodemographic variables (including sex, educational attainment and marriage), parent psychopathology, and childhood adversity as a control (additional details available upon request).</p>2<p>Each row represents a separate bivariate model; some models do not include data from all countries if the country is missing the variable. India and Brazil were dropped in the bivariate model for Combat, Exposure to War and Refugees; and Brazil was dropped in the bivariate model for Natural Disaster. For Israel, the entire sample is coded “Yes” for Exposure to War with the age of onset set to the age they moved to Israel.</p>3<p>Some countries were missing part of the trauma variables and were coded “No” for those variables in the multivariate models: Combat, Exposure to War and Refugee were all coded “No” for India and Brazil; and Natural Disaster was also coded “No” for Brazil. For Israel, the entire sample is coded “Yes” for Exposure to War with the age of onset set to the age they moved to Israel.</p>4<p>For number of events, the last odd ratio represents the odd of the number or more. For example, for the attempt among ideators, 6 events represent 6 or more events (i.e., 6+ events).</p