ideation and from suicidal ideation to attempt or death,
we focus on two theories that do so. Indeed, under­
standing of this distinction is of crucial importance.
First, Joiner’s
interpersonal theory of suicide (figure 1)
posits that the coexistence of high levels of perceived
burdensomeness (ie, feeling a burden on others) and
low levels of belongingness (ie, feeling alienated or that
you do not belong), and being hopeless that these states
will not change, lead to the development of suicidal
desire (ie, suicidal ideation). Suicidal desire is a
necessary though not sufficient cause for a suicide
attempt. However, if a person with high suicidal desire
acquires the capability to attempt suicide, then the risk
of a serious suicide attempt is increased. Acquired
capability comprises reduced fear of death and increased
tolerance for physical pain. According to the theory,
exposure to and encounter with previous painful
experiences increase an individual’s tolerance for the
physical-pain aspects of self-harm through habituation
processes. The core components of the theory have
attracted considerable research attention.
Second, the integrated motivational-volitional model
of suicidal behaviour
conceptualises suicide as a
behaviour (rather than a byproduct of mental disorders)
that develops through motivational and volitional
phases (figure 2). The motivational phase describes the
factors that govern the development of suicidal ideation
and intent, whereas the volitional phase outlines the
factors that determine whether an individual attempts
suicide. This model integrates the key factors from
earlier theories into a detailed map of the suicidal
process from thoughts to acts of suicide. Whereas
belongingness and burdensomeness are paramount in
the final common pathway to suicide in the interpersonal
theory, feelings of defeat (ie, feeling defeated after
triggering circumstances) and entrapment (ie, unable to
escape from stressful, humiliating, or defeating
circumstances) are posited to be of most importance
within the integrated motivational-volitional model.
When an individual feels both defeated and trapped, the
likelihood that suicidal ideation will emerge increases
when motivational moderators (eg, low levels of social
support) are present. The integrated motivational-
volitional model draws on the pioneering research done
by Williams
and others into social-rank theory, the cry-
of-pain and arrested-flight hypotheses, the differential-
activation hypothesis, and the theory of planned
Whereas the interpersonal theory of
suicide posits that acquired capability establishes
behavioural enaction (ie, suicide attempts), it is just one
of several (volitional phase) factors within the integrated
motivational-volitional model posited to increase the
likelihood of a suicide attempt. Such factors include
exposure to the suicidal behaviour of others, impulsivity,
and having access to the means of suicide. Although the
integrated motivational-volitional model is new,
empirical evidence supports its usefulness.
Psychological risk and protective factors
The factors associated with suicide risk can be classified
into four groups: personality and individual differences,
cognitive factors, social factors, and negative life events
(panel 2). In reviewing these factors, we summarise what
is known to date, but do not exhaustively describe the
potential mechanisms through which these factors
might affect suicidal behaviour, which is an extremely
important goal for future research. We selected these
factors because they feature in the theoretical models,
have received research attention in the literature, or are
promising candidates for the future. Each of these factors
might contribute to the emergence of suicide risk
independently or together with other factors. Some of the
factors are associated with the emergence of suicidal
ideation, whereas others increase the likelihood that
suicidal thoughts will be acted on.
Personality and individual differences
Factors related to personality and individual differences
are of interest because they are fairly stable in adulthood,
often have known biological bases, are affected by the
environment, and affect cognition and emotion.
Although hopelessness is usually operationalised as a
state factor (ie, a factor that varies over time), we include
it in this section to emphasise that it also has trait
components (ie, components that are relatively stable
over time),
and future research should investigate the
relative predictive usefulness of state versus trait
hopelessness. Hopelessness, defined as pessimism for
the future, is a strong predictor of all indices of suicidal
ideation and behaviour.
In a classic study, Beck and
were able to predict 91% of all suicides from
I am alone
Desire for
I am a burden
for suicide
(or near-lethal)
suicide attempts
Figure 1:
Interpersonal theory of suicide
Figure reproduced fromVan Orden and colleagues
by permission of the
American Psychological Association.
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