Suicide prevention
Authors:   , van Bentum Jaël Sierra 
Published: January 2024

This dissertation explored the effectiveness of an add-on module called Eye Movement Dual Task (EMDT) for treating intrusive suicide-related imagery, investigated identifying high-risk groups prone to suicide, and explored the experimental approach of intrusive memories and dual tasks. Chapter 1 provides a general introduction and highlights the global impact, prevalence rates, and demographic patterns of suicide. It explores at-risk populations, specific risk factors, intrusive suicidal mental imagery, and the challenges in predicting suicide. Chapter 2 investigates a risk marker that seems a new phenomenon – suicidal mental imagery. We describe theoretical approaches for suicide ideation and suicidal behavior and propose a model of suicidal intrusions by describing one of the assumed mechanisms in the etiology of suicide. Chapter 3 describes the initial stages of translating known experimental approaches (eye movements and dual tasks) to a clinical setting. This pilot study (N=6) aimed to evaluate the safety, tolerability, and feasibility of the EMDT add-on treatment based on Eye Movement Desensitization and Reprocessing (EMDR) but with omission of the installation of the positive cognition phase. Chapter 4 describes the study protocol of the Simagery project. This paper described the trial procedures for adding an EMDT intervention to regular treatment that may reduce the frequency and vividness of suicidal imagery. Chapter 5 describes the development of a new instrument (Suicidal Intrusions Attributes Scale; SINAS) to assess the severity and characteristics of suicidal intrusions and examines its psychometric properties. The brief SINAS measures six attributes of suicidal intrusions: frequency, controllability, closeness to a suicide attempt, distress/vividness, and compulsiveness. Chapter 6 includes results of a multi-center RCT on the efficacy of the EMDT add-on module. Adult suicidal psychiatric outpatients (N=91) with depressive symptoms were recruited across eight mental health institutions in the Netherlands. The primary outcome was severity (SINAS) and frequency (Clinical Interview for Suicidal Intrusions; CISI) of suicidal intrusions at 1-week posttreatment and 3-month follow-up. Secondary outcomes included suicidal ideation, depressive symptoms, hopelessness, and rumination. Chapter 7 focuses on one specific risk group, namely individuals with autism. Our study explores incidence rates of lifetime suicidality and suicidal ideation in the past month in a Dutch cohort (Netherlands Autism Register) of autistic adults, and particular risk factors associated with suicidality in autism. Chapter 8 continues to evaluate the components and characteristics of suicidal intrusions. Our study aimed to investigate the association between the subscales of childhood maltreatment (i.e., physical abuse and neglect, emotional abuse and neglect, and sexual abuse) and the occurrence of suicidal intrusions taking age, gender, posttraumatic stress disorder (PTSD) diagnosis and depressive symptoms into account. Chapter 9 examined the impact of two depression treatments, cognitive therapy (CT) and interpersonal therapy (IPT) on suicidal ideation using data from a previously conducted single-center RCT (Step-D). We used time-lagged mixed-effects models to evaluate the influence of depression treatment on suicidal ideation, and examine the temporal relationship between depressive symptoms and suicidal ideation during each therapy session. Chapter 10 describes a meta-analysis exploring the efficacy of cognitive interventions, including eye movements, in lab settings to reduce intrusive memories. We evaluated the efficacy of cognitive interventions compared to control in reducing intrusion frequency and PTSD symptoms in healthy individuals using the Trauma Film Paradigm. In chapter 11, we developed an Intrusion Film Paradigm (similar to Trauma Film Paradigm) that induced fleeting/temporary suicide-related intrusions. The chapter proceeds to evaluate the impact of eye movements to reduce the vividness and emotionality of suicide-related images in a healthy student sample. Chapter 12 concludes this dissertation and provides an overview of the empirical findings in this dissertation and discuss theoretical, methodological, and clinical implications for suicide prevention research and treatment strategies.