In the current paper, we examined the literature on empirically demonstrated risk factors for suicidal behavior and demonstrated how the Interpersonal Theory is able to account for these facts about suicidal behavior. The theory involves the assumption that, to a large extent, the same mental processes underlie all forms of suicidal behavior. Thus, when looking to the literature on suicidal behavior, available data should be consistent with the role of all constructs in the development of suicidal desire. – depict the hypothesis that empirically-supported risk factors for suicide elevate risk because they are indicators of thwarted belongingness, perceived burdensomeness, or the acquired capability. Our discussion illustrated mechanisms whereby risk factors influence the constructs of the theory. This description of mechanisms underlying proximal risk for suicidal behavior provides a parsimonious account for why the majority of individuals who possess a given risk factor will not attempt or die by suicide – few risk factors increase all components of the Interpersonal Theory. The theory also provides explanations for heretofore difficult to explain epidemiological facts about suicide – including the gender distribution and prevalence of different forms of suicidal behavior – facts that available theories are unable to explain fully.
One of the most consistent findings with regards to the epidemiology of suicidal behavior is its gender distribution. Male suicides outnumber female suicides worldwide, yet far more females than males are engaging in ultimately non-lethal suicidal behavior. Studies suggest that women may be more likely to experience many risk factors that increase—or indicate the presence of—thwarted belongingness and perceived burdensomeness, including major depression (i.e., females are approximately twice as likely as males to suffer from Major Depression; Nolen-Hoeksema, Larson, & Grayson, 1999
). In addition, data indicate that women rank helping others, having a close family, and being loved by loved ones significantly higher than do men as sources of happiness (Crossley & Langdridge, 2005
), suggesting that when these potential sources of happiness are absent, women are particularly likely to perceive
thwarted belongingness and high burdensomeness, and thus suffer greater emotional pain than men in the same situations. However, because females on the whole have fewer experiences that inure them to fear of self-injury (e.g., exposure to guns, physical fights, violent sports, etc.), and because they have lower pain and fear tolerance than males (Berkley, 1997
), they may be less able to develop the acquired capability for suicidal behavior than are males. Therefore, although women may be more likely than males to desire suicide, they are less likely to die by suicide.
The Interpersonal Theory is also able to explain the prevalence of suicidal behavior. The theory involves three conditions that, when present simultaneously, are sufficient to result in lethal (or near lethal) suicide attempts. As each of these conditions is relatively rare, and their confluence more so, the theory is consistent with the rarity of suicidal behavior itself.
Available theories are unable to explain these aspects of suicidal behavior as these theories assume that risk for suicide is elevated solely through increasingly severe levels of desire for suicide. This assumption is exemplified in several descriptive models that account for the prevalence of suicidal behavior by positing the necessary presence of numerous risk factors for suicidal desire. These models, however, are unable to explain facts about suicide such as the gender distribution and seasonal variation, and lack the level of precision needed to prospectively predict suicidal behavior. In addition, as noted by Prinstein (2008)
, available theories do not, for the most part, address both intra-individual and inter-individual factors. The Interpersonal Theory emphasizes the role of acquired capability—a primarily intra-individual factor—as well as the role of thwarted belongingness and perceived burdensomeness—intrapersonal factors (i.e., emphasizing perceptions) that transact with the interpersonal environment.
Thus far, we have posited that the simultaneous presence of the theory’s constructs is sufficient, but not necessary, for suicidal behavior to occur. Thus, other pathways to suicidal behaviors are possible. However, a testable alternative is that the theory’s constructs represent the etiological mechanisms that underlie all
forms of suicidal behavior. This alternative contrasts with many existing theoretical accounts. Consider, Baechler’s (1979)
taxonomy of suicide that proposes all suicidal behavior seeks to solve a problem, but that the problem “solved” by suicide varies and results in types of suicide, each with different etiological origins, including escapist suicides (i.e., escape from grief or punishment), aggressive suicides (i.e., vengeance or blackmail), oblative suicides (i.e., sacrifice), and ludic suicides (i.e., proving onself; Shneidman, 2001
). A recent review of the theoretical literature on suicide (Maris, Berman, & Silverman, 2000
) addresses this assumption by asking, “Is suicide one thing or many things?” and answers, “it seems clear that the answer is ‘many’” (p. 50). We suggest that this assumption has been accepted because of the relative inability of previous theories to comprehensively explain and predict suicidal behavior. We also acknowledge that the question proposed by Maris and colleagues (2000)
– “Is suicide one thing or many things?” – is an empirical one and is in need of scientific scrutiny. Further, the assumption that the same mechanisms underlie all suicidal behaviors—if it were supported—would greatly enhance the clinical utility of the theory. It is this application of the theory—clinical applications—to which we now turn.
One of the primary tasks facing clinicians working with suicidal patients is the assessment of the degree of risk faced by individual patients. Suicide risk assessment frameworks are formalized procedures for clinicians that synthesize the research on the many documented predictors of suicide and provide structured ways to assess both current and more long-standing risk. Applying the Interpersonal Theory to risk assessment suggests that risk assessment frameworks should explicitly address the degree to which patients are currently experiencing thwarted belongingness and perceived burdensomeness, as well as the degree to which they have acquired the capability for lethal self-harm. Risk assessment grounded in the Interpersonal Theory, if supported empirically, will allow for a more parsimonious and clinically useful conceptualization of the etiology of suicide because this conceptualization does not presume that to assess individuals’ degree of risk for suicide requires measurement (or estimation of) a vast number of risk factors. For more specific recommendations on using the Interpersonal Theory in suicide risk assessment (as well as treatment and prevention), readers are referred to Joiner, Van Orden, Witte, and Rudd (2009)
Clinical care for suicidal patients also involves treatment (i.e., psychotherapy and pharmacotherapy) aimed to reduce risk for engaging in suicidal behavior. Public health campaigns also aim to prevent suicidal behavior by targeting all individuals or those at elevated risk for developing thoughts about suicide or engaging in suicidal behavior. We propose that thwarted belongingness and perceived burdensomeness (as well as hopelessness concerning these states) are dynamic (i.e., frequently-changing) factors, while acquired capability, once acquired, is relatively stable and unchanging. These aspects of the theory are relevant for treatment. The theory includes a clearly delineated danger zone at the intersection of perceived burdensomeness, thwarted belongingness, and the acquired capability, and thus yields a clear prediction about what components of suicide interventions will be most effective at treating suicidal symptoms. According to the theory, interventions that directly or indirectly address perceived burdensomeness and thwarted belongingness should produce the best outcomes among suicidal individuals. The acquired capability would be relatively difficult to effectively address in treatment since a therapist is not able to modify a patient’s history, but this aspect of the theory does provide a clear prediction regarding who may benefit most from suicide focused preventive interventions: specifically, those who have a history fraught with painful and provocative experiences. The theory also suggests that prevention efforts targeting thwarted belongingness and perceived burdensomeness may be effective. For example, public health campaigns promoting the importance of maintaining social connections and social contributions could impact suicide rates. Using the Interpersonal Theory to improve clinical care for suicidal patients and as a basis for suicide prevention efforts would, we suggest, support Lewin’s (1951)
claim that “there is nothing so practical as a good theory” (p. 169).