Backgrounds: Many autistic people in mental health are suicidal. This study evaluated the effectiveness of dialectical behavior therapy (DBT) v. treatment as usual (TAU) in reducing suicidal ideation and suicide attempts.
Methods: At six Dutch mental health centers, 123 outpatients (18-65 years) with DSM-5 diagnosed autism spectrum disorder (ASD) and suicidal behavior were randomly assigned to the DBT intervention group (n = 63) or TAU control group (n = 60). Assessments were conducted at baseline, post-treatment at 6 months and 12-month follow-up. The primary outcomes were severity of suicidal ideation and frequency of suicide attempts. The severity of depression and social anxiety were secondary outcomes.
Results: At end-of-treatment, DBT significantly reduced both suicidal ideation (z = -2.24; p = 0.025; b = -4.41; s.e. = 197.0) and suicide attempts (z = -3.15; p = 0.002; IRR = 0.046; s.e. = 0.045) compared to TAU, but lost statistical significance at the 12-month follow-up. Depression severity significantly decreased with DBT (z = -1.99; p = 0.046: b = -2.74; s.e. = 1.37) remaining so at 12 months (z = -2.46; p = 0.014; b = -3.37; s.e. = 1.37). No effects were observed on social anxiety. Severe adverse events included two suicides in the TAU condition.
Conclusions: DBT is an acceptable, safe, and short-term effective intervention to reduce suicidal ideation and suicide attempts in autistic adults with suicidal behavior.
Keywords: autism; dialectical behavior therapy; suicidal behavior; suicidal ideation; suicide attempts.