Autistic Traits and Suicidal Ideation in Adolescents with Major Depressive Disorder: Is Depression a Mediator, a Predictor, or Both?

Objective: Adolescents with autistic traits (ATs) experience higher rates of depression and suicidal behavior. This study aims to investigate the relationship between ATs, depressive symptoms, and suicidal ideation (SI) in adolescents with MDD. Methods: Seventy adolescents were included aged 11-18 diagnosed with MDD. Participants were evaluated with the Columbia-Suicide Severity Rating Scale (CSSR-S), Beck Depression Inventory (BDI), and ATs using the Autism Spectrum Quotient (AQ). Results: Three groups were compared: those without suicidal thoughts (ST-), suicidal thoughts (ST+), and suicide attempts (SA). While SA group scored significantly higher on the C-SSRS, BDI, and AQ compared to the ST-; ST+ and SA groups didn’t differ. The mediating role of depression was investigated via a Bayesian mediator analysis for CSSR-S subheaders of current and lifetime suicidal ideation and ideation intensity. The effect of BDI scores on current suicidal ideation was β=0.08 (CI[0.04-0.13]), which was consistent with lifetime suicidal ideation with the same effect size β=0.08 (CI[0.03-0.13]). For current suicidal ideation and its intensity, autistic traits had an indirect effect through BDI scores, with an indirect mean of 0.050 (CI[0.02-0.10]). For lifetime suicidal ideation, autistic traits exhibited both a direct (β=0.09, (CI[0.01-0.16]) and an indirect effect through depression scores, with a mean of 0.052 (CI [0.015-0.102]). Conclusion: The complex interplay between ATs, depressive symptoms, and SI in adolescents diagnosed with MDD suggests that interventions addressing ATs could be vital in reducing suicidal risk among adolescents, emphasizing the need for comprehensive mental health strategies.