32
Series
this association showed support for this link. A
distinction has been noted between brooding rumination,
in which a person dwells on his or her symptoms, and
reflective pondering, in which a person contemplates the
reasons for his or her symptoms and potential solutions,
with brooding rumination being more strongly associated
with suicidal thoughts and attempts.
70–72
Rumination has
also been associated with increased symptoms of
depression, hopelessness, and impaired problem solving;
an important aim for future research is to clarify how
these factors might work together to increase the risk of
suicidal behaviour.
Thought suppression
Thought suppression refers to attempts to intentionally
stop thinking unwanted thoughts. During the past
25 years, Wegner and other researchers
73,74
have reported
that thought suppression paradoxically increases the
frequency of specific unwanted thoughts, and might be a
mechanism through which several forms of psycho­
pathology develop. Findings from several studies
75,76
showed that a tendency to suppress unwanted thoughts
was associated with both suicidal ideation and attempts,
and that thought suppression mediated the association
between emotion reactivity and the occurrence of self-
injurious thoughts and behaviour.
75
Autobiographical memory biases
People who engage in suicidal behaviour have a
decreased ability to recall specific autobiographical
memories,
77
which might in turn impair their ability to
imagine the future and to engage in effective problem
solving, thus increasing the likelihood of suicidal
behaviour.
78,79
Some evidence suggests that auto­bio­
graphical memory biases result in part from previous
abuse or from the presence of an affective disorder,
80
and
as such represent a potential mechanism through which
abuse and affective disorders could lead to suicidal
behaviour.
Belongingness and burdensomeness
Durkheim,
81
Shneidman,
21
and most recently Joiner
15
have proposed that thwarted belongingness predisposes
to the development of suicidal thoughts and behaviour.
Consistent with these theories, lack of social
connectedness and subjective perception of thwarted
belongingness have been associated with suicide
ideation
82,83
and suicide attempts.
84–86
A person’s perceptions that he or she is a burden to
others is an independent predictor of suicide ideation in
a range of samples, including older adults
87
and people
with chronic pain.
88
Perceived burdensomeness also has
been shown to mediate the association between
perfectionism and suicide ideation,
89
and to remain
predictive of ideation even after controlling for factors
such as depression and hopelessness.
87
Consistent with
the interpersonal theory of suicide, the interaction of
perceived thwarted belongingness and burdensomeness
is predictive of suicide ideation, even after controlling for
depressive symptoms.
90
Fearlessness and pain insensitivity
As suicidal behaviour often includes infliction of
physical pain on the body, the association between
suicide risk and both pain sensitivity or tolerance and
fearlessness about death has been examined. Although
almost all research into pain sensitivity has focused on
non-suicidal self-injury, increased pain thresholds and
tolerance have been reported in suicidal adolescents.
91
More research is needed to establish whether changes
in pain sensitivity are a cause or result of suicide
ideation or behaviour; how these changes vary as a
function of suicidal history and across the lifespan
requires clarification. Research findings suggest that
suicide attempters have higher fearlessness about injury
and death than do non-suicidal controls, and that this
difference might account for why men are more likely to
die by suicide than are women.
92,93
Problem solving and coping
That people who attempt to kill themselves have
difficulties with problem solving or coping is, perhaps,
self-evident. Nevertheless, study findings have consistently
shown a link between suicidal behaviour and deficits in
both interpersonal problem solving and coping.
94,95
In view
of the cross-sectional nature of most studies into this
topic, however, the direction of this association is not clear.
Moreover, these associations seem to be mostly accounted
for by the presence of depression.
96
Agitation
Agitation, which is often conceptualised as a state of
anxious excitement or disinhibition, has been linked
with suicidal behaviour in many studies.
97
For instance,
in a chart study
98
of 76 patients who died by suicide
during hospital admission, 79% had severe anxiety or
agitation shortly before their death.
98
Agitation has been
hypothesised to be one potential mechanism through
which bipolar disorder, medical illness, and the
prescription of certain psychiatric medications might
increase the risk of suicidal behaviour.
99–101
Recent
research suggests that agitation is especially predictive of
suicide attempts among people who have high capability
for suicide.
102
Implicit associations
People with a recent history of suicidal behaviour show an
implicit mental association between death and the self.
103
Findings from research
103,104
using the implicit association
test showed that this association distinguished suicide
attempters from distressed non-attempters presenting for
emergency psychiatric treatment (ie, suicide attempters
responded more quickly [measured in milliseconds] when
pairing stimuli related to death and self than they did
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