1. Canadian Psychological
Association
Annual Convention,
June 2015, Ottawa, Ontario
NON-SUICIDAL SELF-INJURY PREDICTS INCREASED SUICIDAL IDEATION, SUICIDE ATTEMPTS, AND ACQUIRED CAPABILITY FOR SUICIDE
Christine E. Lambert, Queen’s University, Kingston, Ontario
Abstract
Hypotheses
Results II
Non-suicidal self-injury (NSSI) has been defined as the direct and deliberate destruction of one’s own body tissue without suicidal intent. Despite the lack of suicidal intent characteristic of NSSI, a history of NSSI is predictive of suicide attempts. However, little empirical research has assessed NSSI as a risk factor for suicide. According to the Interpersonal Theory of Suicide (ITS), a person will not die by suicide without the simultaneous presence of three characteristics: thwarted belongingness, perceived burdensomeness, and acquired capability for suicide (Van Orden et al., 2010). Acquired capability for suicide consists of fearlessness of death and increased pain tolerance, and emerges via repeated exposure to fear-inducing and physically painful stimuli. According to the ITS, NSSI could be related to increased risk of death by suicide by increasing acquired capability for suicide. The current study investigated whether NSSI was a significant predictor of suicidal ideation or suicide attempts. Results showed that NSSI was a significant predictor of both, outperforming some of the traditional measures. NSSI also significantly predicted increased acquired capability for suicide and increased pain tolerance. These findings support the value of NSSI in predicting suicide attempts, as well as the theory that NSSI increases risk of death by suicide by increasing acquired capability for suicide.
Study 1:
Hypothesis 1: Psychache, hopelessness, depression, and NSSI will all be significant predictors of suicide attempts.
Hypothesis 2: Psychache, hopelessness, depression, and NSSI will all be significant predictors of suicide ideation.
Hypothesis 3: Consistent with previous research, hopelessness and depression will predict suicide motivation (3a), and psychache and NSSI will predict suicide preparation (3b)
Study 2:
Hypothesis 1: Both self-harmer status and severity of self-harm will predict higher capability for suicide.
Hypothesis 2: Both self-harmer status and severity of self-harm will predict higher pain tolerance.
Table 2. Study 1 Regression Coefficients
Hyp. 1: Suicide Attempts
Hyp. 2: Total Suicidal Ideation
Hyp. 3a: Suicide Motivation
Hyp. 3b: Suicide Preparation R2
.17**
.72**
.44**
.46**
Statistical Predictor β p
Depression
.054
.694
.136
.207
.261
.065
-.022
.825
Hopelessness
-.039
.781
.107
.309
.208
.064
.114
.273
Psychache
.191
.330
.263
.014
.090
.475
.314
.002
NSSI
.283
.067
.395
.000
.269
.032
.436
Method
Participants
Study 1: 212 students, age years (M = 19.63, SD = 1.79), 191 women
Study 2: 182 women, age years (M = 18.83, SD = 1.37)
Materials
Suicide history questions, Beck Depression Inventory-II (BDI-II), Beck Hopelessness Scale (BHS), Beck Scale for Suicide Ideation (BSS), Psychache Scale, Deliberate Self-Harm Inventory (DSHI), Interpersonal Needs Questionnaire, Acquired Capability for Suicide Scale, measure of pain tolerance across 5 trials using a Model 50 FPX Algometer
NSSI was measured operationally using the DSHI: participants respond yes/no to 17 forms of intentional, non-suicidal self-injury, including cutting, burning, scratching, biting, banging, etc.
** Significant at the 0.01 level (2-tailed); * Significant at the 0.05 level (2-tailed).
Study 2
Individuals with a history of self-harm (M = 41.81, SD = 11.40) had significantly higher acquired capability for suicide scores than those without (M = 35.56, SD = 11.03), t(178) = 3.72, p < DSHI total scores were significantly, positively correlated with acquired capability for suicide, r = .337, p < .001.
Those with a history of NSSI (M = 7.04, SD = 3.26) had significantly higher pain tolerance scores than those without (M = 5.76, SD = 2.45), t(174) = 2.98, p = Significant correlation between severity of self-harm and pain tolerance, r = .155, p = .039.
Background
Hopelessness & Depression: established statistical predictors of suicidal ideation and death by suicide
Psychache: intense psychological pain/aching/anguish. Posited by Shneidman (1993) to be a necessary condition for death by suicide: the individual deems that the only solution to the pain is cessation of consciousness. All other factors (depression, etc.) are considered secondary.
Interpersonal Theory of Suicide (ITS): suicide will not occur without the presence of 2 interpersonal factors and Acquired Capability for Suicide (Van Orden et al., 2010)
Interpersonal Factors
Perceived Burdensomeness: the belief that one is a burden to the people around him, and that others would be better off if (s)he were gone
Thwarted Belongingness: feeling different or disconnected from other people; a frustrated human need to belong
Acquired Capability for Suicide (ACS)
Consists of Pain Tolerance and Fearlessness of Death
Develops gradually through repeated exposure to painful and provocative events, such as self-injury
Therefore, NSSI may increase risk of death by suicide by increasing Acquired Capability for Suicide
Suicide Motivation: suicide ideation/desire to die by suicide
Suicide Preparation: a more severe form of suicide ideation; consists of making plans or taking actions toward dying by suicide
Conclusions
Only NSSI was a marginal predictor of suicide attempts due to the low number of attempts in this sample. Suggests that with more power, NSSI would outperform traditional predictors.
Only NSSI and Psychache were significant predictors of suicidal ideation - outperformed traditional predictors.
Only NSSI was a significant predictor of suicide motivation; NSSI and Psychache were significant predictors of suicide preparation – NSSI predicts the more severe subtype of suicidal ideation.
A history of NSSI predicted increased Acquired Capability for Suicide scores – supports hypothesis that NSSI may increase risk of death by suicide by increasing ACS.
A history of NSSI predicted increase Pain Tolerance scores –further support for NSSI increasing risk of death by suicide by increasing ACS hypothesis.
Results I
Table 1. Prevalence of NSSI and Suicide Attempts
Study 1
Study 2
Participants
212
182
Past NSSI
80 (38%)
83 (45%)
68/80 women
All women
Suicide Attempt
7 (3.3%)
14 (7.7%)
References
Holden, R. R., Mehta, K., Cunningham, E. J., & McLeod, L. D. (2001). Development and preliminary validation of a scale of psychache. Canadian Journal of Behavioural Science/Revue Canadienne Des Sciences Du Comportement, 33(4), 224–232.
Shneidman, E. S. (1993). Suicide as psychache. The Journal of Nervous and Mental Disease.
Van Orden, K. A., Witte, T. K., Cukrowicz, K. C., Braithwaite, S. R., Selby, E. A., & Joiner, T. E. (2010). The interpersonal theory of suicide. Psychological Review, 117(2), 575–600.
Correspondence
Christine E. Lambert, Department of Psychology, Queen’s University, Kingston, ON K7L 3N6, Canada.