Background & Rationale: Suicidality is extremely common in youth with autism spectrum disorder (ASD), affecting approximately 66% of individuals. Importantly, individuals with ASD are 7 times more likely to die by suicide than individuals without ASD, and these rates are rising. Yet little is known about why some autistic individuals experience these thoughts and behaviours, and others do not. In the general population, there is a growing body of research investigating the interaction between biological vulnerabilities (how our bodies respond to stress, or an altered hypothalamic pituitary adrenal [HPA] axis) and cognitive factors (how we think in stressful situations) in the development of suicidality. In times of stress, this altered HPA-axis (aHPA) reactivity prevents individuals from being able to cope successfully, and stop suicidal thoughts and behaviours. To date, no study has examined if aHPA reactivity is related to suicidality in autistic individuals, nor how cognitive flexibility and impulsivity may interact with this altered stress response to heighten the risk of suicidality in autistic individuals.
Objective & Hypothesis: This project aims to address this knowledge gap by investigating: 1) the relation between aHPA reactivity (biological vulnerability) and lifetime suicidality in autistic youth and 2) if how an individual thinks during stressful situations (cognitive processing) strengthens this relationship. It is expected that aHPA reactivity is associated with lifetime suicidal attempts, and cognitive difficulties will moderate, or strengthen this relationship.
Sample: One-hundred and thirty youth with ASD (12-18 years of age) and their caregivers will participate in this study.
Measures: Autistic youth's reactivity to stress will be determined by examining cortisol levels (stress hormone found in their saliva) during and after a social stress test (TSST). Cognitive flexibility and impulsivity will be measured using questionnaires (BRIEF), standardized assessment tools (D-KEFS), and two computerized tasks (Go/No-Go Tasks). Lifetime and recent suicidality will be measured using a comprehensive interview (SITBI) with youth and their caregivers, independently, and a brief self-report questionnaire (SBQ). Age, sex, intelligence (WASI-II), medication use, and mental health symptoms (BASC-3) will be controlled for in the analyses.
Procedure: Participation will involve two back-to-back lab visits, each lasting 2 to 3 hours. Session 1 will involve: consent, psychosocial stress test and saliva swabs, and cognitive tasks. At the same time caregivers will complete the suicidality interview and questionnaires. In session 2, youth will complete the suicidality interview, IQ measure, a cognitive task, and questionnaires.
Potential Impact: This is the first study to investigate potential risk factors for suicidality in autistic youth, filling a substantial gap in existing knowledge. Understanding how biological and cognitive vulnerabilities interact to heighten the risk of suicidality in autistic youth is critical for preventing lifelong problems and premature death in this extremely vulnerable population.
Next Steps: Findings will act as a first step in developing a comprehensive risk model of suicidality for individuals with ASD, and will help to support future projects and grant applications. Clinically, study findings will fill a significant gap in clinical care related to preventative and intervention strategies for autistic individuals.
