Exploring new ways to assess the suicidal process in practice and research

Summary Introduction Each year, more than 700,000 people die by suicide worldwide, and approximately 1,800 people end their lives in the Netherlands. For every person who dies by suicide, an estimated 20 others engage in non-fatal suicide attempts, and many more people consider taking their own lives. Despite decades of research, the ability to predict and prevent suicidal behaviour has seen little improvement. The aim of this thesis was to explore new ways to assess the psychological suicidal process in both clinical practice and research. The research presented is based on the CASPAR study (Continuous Assessment for Suicide Prevention And Research), a feasibility study that developed and evaluated mobile health (mHealth) interventions as a component of standard outpatient treatment for depressed and suicidal patients. This thesis is divided into two parts: Part 1 explores new ways to assess the suicidal process in clinical practice (Chapters 2, 3, and 4), while Part 2 examines new ways to assess the suicidal process in research (Chapters 5, 6, and 7). Part 1: Exploring new ways to assess the suicidal process in practice Chapter 2 describes the rationale and protocol of the CASPAR study. The feasibility of using two apps in addition to regular treatment was assessed: a safety planning app and a self-monitoring app. In Chapter 3, the findings of this study are presented. Results suggest that smartphone-based safety planning and self-monitoring are usable and acceptable in clinical practice. However, further research is needed to integrate these apps into routine treatment. Chapter 4 presents a meta-analysis on the effectiveness of safety planning interventions in reducing suicidal behaviour and ideation. The analysis provides evidence supporting its effectiveness in reducing the risk of suicidal behaviour, but not in significantly alleviating suicidal ideation. Part 2: Exploring new ways to assess the suicidal process in research To explore the suicidal process, the self-monitoring data gathered in the CASPAR study using Ecological Momentary Assessment (EMA) was analysed. Chapter 5 presents a proof-of-concept study that tracks fluctuations in suicidal ideation over a period of three to six months. Findings indicate that trends in the severity of suicidal ideation can be tracked over months and that these patterns vary between individuals. Changes in these trends may be detectable at an early stage. Chapter 6 investigates whether psychological risk factors predict suicidal ideation as hypothesised by the Integrated Motivational-Volitional model of suicidal behaviour. Results indicate that the predictive value of the proximal risk factors varies both across patients and over time. Chapter 7 applies Dynamic Time Warping analysis to examine how suicidal symptoms cluster and evolve over time in individual patients. This method provides personalised insights into suicidal ideation trajectories, emphasizing the need for tailored interventions based on individual symptom patterns. General discussion This thesis explored new ways of assessing the suicidal process in practice and research. It highlights the potential of mobile safety planning and self-monitoring as an adjunct to regular treatment for suicidal patients. However, successful implementation in clinical practice requires addressing integration challenges. The findings support safety plans as an effective intervention for reducing the risk of engaging in suicidal behaviour and underscore the need for continuous assessments in clinical practice. Furthermore, idiographic research using EMA has demonstrated its feasibility and effectiveness in capturing real-time symptom changes within patients, thereby offering valuable insights into individual trajectories. This thesis revealed that each individual follows a distinct pathway to suicidal ideation, reinforcing the need for suicide prevention strategies tailored to individual needs. These advancements lay a foundation for further development in the field of suicide prevention, incorporating a within-person perspective and real-time monitoring in both clinical practice and research contexts.