Cost-effectiveness of dialectical behavioural therapy versus treatment as usual for autism with suicidal behaviours: single-blind randomised controlled trial

Objective This study evaluated the cost-effectiveness of dialectical behaviour therapy (DBT) compared to treatment as usual (TAU) for autistic adults with suicidal behaviours. Method In a randomised controlled trial, 123 autistic outpatients were assessed over 12 months. Healthcare costs and societal costs were calculated in accordance with the Dutch standard. Outcomes were quality-adjusted life years (QALYs) and treatment response, defined as a reduction of at least 50% in symptoms of suicidal ideation from t(0)-t(12) as measured by the Suicidal Ideation Attributes Scale (SIDAS), plus achieving SIDAS < 20 at t(12) (i.e. below the clinical threshold). Results From the healthcare perspective, DBT cost <euro>371 less than TAU while gaining an additional 0.184 QALYs, with a 64% likelihood of being the dominant treatment option. From the societal perspective, DBT has higher costs than TAU by <euro>232 per QALY gained, which can be considered cost-effective given a willingness-to-pay of <euro>50,000 per QALY. DBT also showed better treatment response rates, with less suicidal ideation, at lower costs than TAU. Sensitivity analyses supported these findings. Conclusion DBT is a novel treatment for autistic adults with suicidality. It fills a significant treatment gap in lieu of any evidence-based alternative for this population. DBT reduces suicidality, enhances quality of life and is cost-effective across healthcare and societal perspectives, encouraging broader adoption. Future research should assess DBT's long-term impacts and its transferability to other countries and map pathways towards upscaled implementation.