Review
Suicidal brains: A review of functional and structural brain studies in association with suicidal behaviour

https://doi.org/10.1016/j.neubiorev.2010.08.007Get rights and content

Abstract

Evidence of an association between a vulnerability to suicidal behaviour and neurobiological abnormalities is accumulating. Post-mortem studies have demonstrated structural and biochemical changes in the brains of suicide victims. More recently, imaging techniques have become available to study changes in the brain in vivo. This systematic review of comparative imaging studies of suicidal brains shows that changes in the structure and functions of the brain in association with suicidal behaviour are mainly found in the orbitofrontal and dorsolateral parts of the prefrontal cortex. Correlational studies suggest that these changes relate to neuropsychological disturbances in decision-making, problem solving and fluency, respectively. As a consequence, the findings from these studies suggest that suicidal behaviour is associated with (1) a particular sensitivity to social disapproval (2) choosing options with high immediate reward and (3) a reduced ability to generate positive future events. Further study is needed to elaborate these findings and to investigate to what extent changes in the structure and function of suicidal brains are amenable to psychological and/or biological interventions.

Research highlights

▶ A review of suicidal neuroimaging literature. ▶ The orbitofrontal and dorsolateral cortex are involved in the suicidal process. ▶ Literature shows a possible link between decision-making and suicidality. ▶ Further neuropsychological and neuroimaging research is necessary.

Introduction

As the global annual rate of suicide approximates 15 per 100,000 individuals, it is estimated that one million people worldwide commit suicide each year (WHO, 2002). Annual rates of non-fatal suicidal behaviour are 10–20 times higher than those of completed suicide (Kerkhof, 2000). Suicidal behaviour thus constitutes a major public health problem, and costs at societal and individual levels are huge. In addition, suicidal behaviour poses a major challenge to clinicians, health care workers and policy makers due to its limited predictability (Hawton and van Heeringen, 2009). Problems in predicting and thus preventing suicidal behaviour are due to the multiplicity of possible causes and a limited insight in predisposing mechanisms.

Based upon the current state of knowledge a stress-diathesis model of suicidal behaviour has been proposed to describe the interaction between proximal risk factors and such predisposing mechanisms (Hawton and van Heeringen, 2009). The vast majority of suicidal behaviours are associated with depression, but indeed require the presence of an additional diathesis or predisposition. In vivo brain imaging is a promising tool for the investigation of the diathesis predisposing to suicidal behaviour, and the last decade has witnessed a steady increase in the number of such studies (Mann, 2005). A first advantage of using brain-imaging techniques is to confirm post-mortem findings of involved brain areas and neurobiological systems such as the serotonin system. Second, brain imaging provides a possibility to demonstrate a biological substrate for neuropsychological changes in relation to suicidal behaviour, thus providing support of a causal interpretation of this relation.

The findings from brain-imaging studies have not been systematically reviewed yet. Imaging studies of suicidal behaviour fall into two broad categories, i.e. the study of the neural correlates of suicidal behaviour directly, and studies addressing clinical traits typically associated with suicidal behaviour, such as aggressive and impulsive behaviours. The current review focuses on the first category of studies and therefore aims at the identification, synthesis and appraisal of structural and functional neuroimaging studies of suicidal behaviour.

Section snippets

Methods

A comprehensive literature search yielded the set of relevant articles for this review. First, we did an electronic search using the Web of Science, MEDLINE, PsycINFO (and PubMed) databases for articles published in English, from 1990 onward. Search terms were suicidal, suicide, suicide attempt, and imaging, CT, MRI, SPECT, PET, fMRI, DTI. Unpublished studies, case reports or conference abstracts were not included in this review. Second, the reference lists of relevant papers were checked

Results

As shown in Fig. 1, the search produced 550 publications. Twenty-two articles met the inclusion criteria and were thus included in this review, categorized as ‘structural imaging studies’ (CT, MRI, DTI) or ‘functional imaging studies’ (SPECT, PET, fMRI).

In the following part of the paper, studies will be reviewed in chronological order; studies from the same research group are reported together. Table 1 summarizes the sample characteristics and detailed results of the reported studies. Fig. 2,

Discussion

Suicidal behaviour constitutes an important public health problem and poses a major challenge to health care because of difficulties in its prediction and thus prevention. This paper reviews studies of the association between structural or functional brain characteristics and suicidal behaviour. Such a review is relevant as knowledge of neural characteristics may contribute to our understanding, and thus to the prediction and prevention of suicidal behaviour.

The findings from this review can be

Conflicts of interest

The authors have neither financial interest in, nor financial support for writing this review.

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