Identifying risk and protective factors for suicide

For all human beings, a core need in life is physical security. It is therefore staggering that, annually approximately 800.000 individuals end their life by suicide (WHO, 2021). Unfortunately, to date, there are still many open questions surrounding the factors contributing to suicidal thoughts, suicidal behavior and suicide. Therefore, the aim of the current thesis was to add knowledge about various risk factors as well as protective factors, that might link to suicide. The results of this thesis show an association between suicidality and the severity of clinical symptoms (e.g. depression severity) and psychological complaints (e.g. hopelessness). With regards to cognitive risk factors, individuals with suicidality showed better social cognitive skills and lower performance on general cognitive (i.e. attention and verbal learning) tasks. Furthermore, we found a relation between self-harm behavior and weaker unconscious associations with words related to suicide/death. People with self-harm behavior also showed less self-compassion, and a lower level of mindfulness was related to a risk factor (entrapment) for suicidal thoughts. We also found individuals with suicidal thoughts to be less flexible in switching from one brain region to another across the brain, which could be an indicator of more rigidity. The results of this PhD thesis contribute to a better understanding of the complexity of suicide and can be used for future studies about treatment and prevention methods. Ultimately, this will lead to an improved quality of life of individuals at risk for suicide and of our society as a whole

Prevalence, course, and determinants of suicide ideation and attempts in patients with a depressive and/or anxiety disorder: A review of NESDA findings

Background: Depressive and anxiety disorders are often associated with suicide ideation (SI) and attempt (SA). However, analyses of prevalence, course, and more specific risk mechanisms are needed to improve knowledge and detection of high risk individuals with depressive and anxiety disorders. Previous studies often lacked statistical power, assessment of detailed determinants and follow-up measurements. Methods: The Netherlands Study of Depression and Anxiety (NESDA), a large cohort study, overcomes some earlier limitations. Scale for Suicide Ideation and Compositive Interview Diagnostic Instrument data were analyzed to report on prevalence of SI and SA. Additionally, important sociodemographic, clinical, psychological, environmental, and neurobiological determinants and course of SI and SA identified in depressive and/or anxiety disorder respondents in 16 NESDA articles were summarized. Results: Within respondents with 12-month diagnosis (n=1,783), SI and 12-month SA prevalence ranged from 17.1-20.1% and 0.8-3.0% respectively across 5 waves during 9-year follow-up and SI was highly recurrent. Both SI and SA were especially associated with comorbid depression and anxiety, higher clinical severity, sleep dysfunctions, higher aggression and hopelessness, and childhood trauma. In the (neuro)biological domain, SI was linked with immune dysregulation and SA with abnormal brain activity during emotion processing and genetic risk. Limitations: Most articles were cross-sectional in nature, preventing causal inferences and no conclusions could be drawn about the overall magnitude of results. Conclusion: SI and SA are multifactorial phenomena and especially prevalent amongst comorbid depressive and anxiety respondents. Considering many overlapping SI and SA determinants, more neurobiological determinants and use of innovative methodological techniques are desirable

Risk factors for suicidality across psychosis vulnerability spectrum

Background: Suicide is a leading cause of death in individuals with psychotic disorders. Risk factors for suicidality across the psychosis vulnerability spectrum are insufficiently known. Methods: For patients (n = 830), siblings (n = 664) and controls (n = 444), suicidality was assessed by the use of a clinical interview. Multilevel modelling was used to investigate risk factors of suicidality. Lastly, risk factor × familial risk interaction effects were examined. Results: Multivariable models revealed a significant relation between suicidality and depressive symptoms across all three groups, and childhood trauma in patients and siblings. The association between suicidality and psychotic-like experiences is more pronounced in siblings compared to controls. Conclusion: Across the psychosis vulnerability spectrum, depressive symptoms and childhood trauma have been associated with suicidality. Clinicians should pay attention to suicidality in individuals at high familial risk for psychosis with psychotic-like experiences