We suggest that integrating research on risk and protective factors with a theoretical foundation can provide clinicians with guidance for risk assessment and intervention. In this section, we introduce a recently proposed theory of suicide, the Interpersonal Theory of Suicide [44•
], as an organizing framework for material reviewed above and material on prevention that follows. The theory proposes two proximal causes of the desire for suicide—thwarted belongingness and perceived burdensomeness. Thwarted belongingness is a painful mental state that results from an unmet need to belong—a need to feel connected to others in a positive and caring way. Perceived burdensomeness involves the mental calculation, “My death is worth more than my life to others” and involves the presence of interpersonal connections that are negatively valenced and thus do not meet the need to belong. Thus, as depicted in , these two constructs—thwarted belongingness and perceived burdensomeness—are referred to collectively as social disconnectedness
. Regarding the effect of social disconnectedness, the theory also proposes that a particularly dangerous level of suicidal desire results from the simultaneous presence of both factors. Importantly, the theory also proposes that suicidal desire is necessary but not sufficient for lethal (or near-lethal) suicidal behavior to result because, simply put, dying by suicide is not an easy thing to do. The theory proposes that suicidal desire must be accompanied by an acquired capability for suicide, which is acquired through habituation to the pain and fear involved in suicidal behavior if lethal (or near-lethal) suicidal behaviors are to result.
Fig. 1 The Interpersonal Theory of Suicide applied to late life. Note that the three inner colored circles represent the three key constructs posited to cause suicide according to the Interpersonal Theory of Suicide. The five boxes represent key risk factors (more ...)
As depicted by the three inner circles in , the theory proposes that a relatively large number of individuals may experience thwarted belongingness or perceived burdensomeness, and a smaller number have acquired the capability for suicide. Crucially, the smaller area of overlap between thwarted belongingness and perceived burdensomeness indicates that fewer individuals will experience both states and thereby fewer will experience more severe levels of suicidal desire. Finally, the area of overlap between all three constructs is especially small, reflecting the fact that very few individuals will concurrently experience thwarted belongingness, perceived burdensomeness, and an acquired capability. Thus, according to the theory, only a very small number of people should die by suicide, although many more may have thoughts about suicide (ie, milder suicidal desire). In this way, the theory is consistent with the finding replicated worldwide and over time that only a small subset of those who think about suicide go on to attempt, and even fewer will die by suicide [45
]. Research conducted on the theory thus far has been promising, especially with regard to the hypotheses regarding suicidal desire [46
], although more research is needed that examines the key outcome of suicide deaths. For an in-depth discussion of the theory’s hypotheses and a review of studies testing the theory, see Van Orden et al. [44•
A key hypothesis of the theory is depicted graphically in . The circle containing thwarted belongingness, perceived burdensomeness, and acquired capability represents the theory’s hypothesis that these three factors are the most proximal to the outcome of suicide. The five boxes outside the circle represent the risk factors for late-life suicide that have received consistent support from psychological autopsy studies—psychiatric illness, social isolation, functional impairment, physical illness and pain, and access to lethal means—and the diagram depicts them as causing thwarted belongingness, perceived burdensomeness, or acquired capability (ie, the dotted lines) because the theory proposes that risk factors elevate risk to the extent that they create one of these proximal causes of the suicidal state. As described above, culture, personality, neurobiological and cognitive processing, and life events may contribute to these factors; thus, those domains surround all other aspects. represents an application of the Interpersonal Theory of Suicide in late life. Specifically, the figure illustrates the hypotheses that psychiatric illness makes individuals vulnerable to thwarted belongingness and perceived burdensomeness (consistent with the fact that many with disorders such as major depression think about suicide but do not die by suicide). Social isolation indicates that the need to belong may be thwarted; functional impairment increases the risk of developing perceptions of burdensomeness; the experience of pain increases acquired capability (by engaging habituation to pain); and older adults’ greater planning and preparation for suicide and use of more lethal means indicate greater acquired capability for suicide.
Clinically, this hypothesis suggests that for interventions to be effective in preventing suicide in older adults, they must reduce existing levels (or prevent the incidence) of thwarted belongingness or perceived burdensomeness, or must block the expression of acquired capability (which is not posited to be amenable to intervention). Thus, the theory proposes that risk assessments need not involve assessments of all known risk factors for suicide in older adults, and interventions need not target all risk factors. Rather, effective risk assessments will involve assessment of key risk factors as well as the degree to which the risk factors create or magnify the theory’s constructs. For example, with an 85-year-old man diagnosed with depression who presents with increasing functional impairment, a clinician using the Interpersonal Theory of Suicide to inform risk assessment would inquire as to whether this man feels like a burden on others. Given that functional impairment is common in later life, whereas suicide is not, examining the psychological effect of risk factors such as functional impairment can elucidate the mechanisms whereby those risk factors may elevate risk, thereby providing a more nuanced assessment and potentially identifying a target for intervention.