Background: Suicide is a worldwide concern, claiming nearly one million lives each year. The causes of suicidal behaviour are unclear, but a variety of biological, psychological, social, and environmental factors are thought to contribute to suicide risk. Many cases of suicidal behaviour cannot be explained by conventional risk proposed by clinical and research observations. Recent research has focused on biomarkers of suicidal behaviour, including brain-derived neurotrophic factor (BDNF). This thesis aims to determine the association between BDNF and suicidal behaviour by reviewing the literature and by analyzing clinical data. An additional aim of this thesis is to explore the associations between social factors and suicidal behaviour, with a particular focus on sex differences within these factors.
Methods: We explored the associations between biological and social risk factors and suicidal behaviour in several ways. We conducted a systematic review to summarize and evaluate the literature regarding BDNF levels and suicidal behaviour. The protocol for this systematic review was designed and published a priori. We performed a qualitative review of the literature and a meta-analysis of studies of serum BDNF and attempted suicide. Then, we assessed the association between serum BDNF and attempted suicide using a case-control study design. We analyzed data collected from the Study of Determinants of Suicide Conventional and Emergent Risk (DISCOVER), and age- and sex-matched study of attempted suicide. In a sample of 250 participants (84 cases of attempted suicide, 104 psychiatric controls, and 93 community controls), we used linear regression analysis to determine the association between BDNF level and attempted suicide, adjusting for age, sex, body mass index, current smoking status, and antidepressant use. Finally, using the same dataset, we explored the associations of a number of social factors with attempted suicide. In a sample of 343 participants (146 cases, 104 psychiatric controls, and 93 community controls), we used logistic regression analyses to determine the associations between social risk factors and attempted suicide in men and women separately. These included age, education level, employment status, marital status, religious practice, stressful life events, and childhood abuse.
Results: Our systematic review included 14 studies. The meta-analysis of three studies of serum BDNF and attempted suicide showed no significant association. The qualitative review of all studies revealed inconsistent findings regarding associations between BDNF and suicidal behaviour. In our study of serum BDNF and attempted suicide in the DISCOVER dataset, attempted suicide was not significantly associated with BDNF level. In our study of social factors for attempted suicide, some sex differences were found: Completion of post-secondary education and religious practice were found to be significant protective factors against attempted suicide only in women, and unemployment and stressful life events were significant risk factors only in men.
Conclusion: This thesis provides important findings about the biological and social risk factors for suicidal behaviour. Understanding the determinants of suicidal behaviour can aid clinicians in identifying and treating vulnerable individuals. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19113 |
| Date | 16 June 2016 |
| Creators | Eisen, Rebecca B. |
| Contributors | Samaan, Zainab, Neuroscience |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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