1 - (IOP18) Extending Access to CBT for Autistic Teens with Intellectual Disabilities and Varied Language Abilities

Background: Autistic teens with intellectual disability (IDD) often experience clinically interfering anxiety (Winch et al., 2022), reduced access to evidence-based mental health care, and significant health inequality (Doherty et al., 2020). Facing Your Fears (FYF), a manualized 14-week group CBT intervention for anxiety in autistic youth (Reaven et al. 2011), was adapted for autistic teens with IDD (FYF:IDD).

Objectives: 1) To conduct a randomized controlled trial (RCT) with autistic teens with IDD and anxiety and examine anxiety reduction (primary outcome), and 2) assess the impact of teen characteristics (expressive language, adaptive behavior) on treatment outcome. 

Methods: Seventy-three autistic teens with IDD participated in the RCT (72.6% male; 26% Hispanic, 72.6% white; Mage=15.3 years, MFSIQ = 56.2, MAdaptive Behavior Composite(ABC)= 59.4) and met criteria for at least one anxiety diagnosis on the Anxiety Diagnostic Interview Schedule-Autism Addendum (ADIS-ASA, Kerns et al., 2017). Language level was identified by module on ADOS-2 (“minimally verbal” = Module 1/2; “fluent speech”=Module 3/4). Teens were randomized to either FYF:IDD or treatment as usual (TAU). Clinicians masked to condition completed Clinical Global Impression Scale-Improvement (CGI-I; Guy, 1976) ratings on the ADIS-ASA for Primary Anxiety diagnosis (i.e., diagnosis with the highest clinical severity rating at baseline), Total Anxiety (i.e., all anxiety diagnoses except specific phobias); and Specific Phobia (i.e., all phobias). There were no pre-treatment differences in IQ, ABC, age, autism severity and anxiety symptoms.  T-tests were used for primary treatment outcomes.

Following TAU, teens crossed-over and completed FYF:IDD (N=53). Fifteen teens were minimally verbal and 38 had fluent speech. Independent samples t-tests were conducted for language level. Regression models were conducted for continuous predictors (ABC).

Results: (1) RCT outcome: Teens randomized to FYF:IDD experienced significant improvement in their Primary Anxiety CGI rating relative to teens randomized to TAU, t(66)=2.71, p=.008. There were no significant differences between groups on the Total Anxiety CGI or Specific Phobia CGI (t-scores < 1.8).

(2) Teen Characteristics: Language level was not significantly related to CGI-I for Primary Anxiety or Specific Phobia; teens who were minimally verbal demonstrated greater improvement (lower CGI-I) for Total Anxiety compared to teens with fluent speech (p=.04). ABC did not significantly predict Primary or Total Anxiety; higher ABC scores predicted greater improvement in CGI scores for Specific Phobias (p=.03).

Conclusion: This is the first RCT of a group CBT anxiety intervention for autistic teens with IDD, marking a critical step toward building an evidence base for mental health interventions in this underserved population. Results suggest that autistic teens with IDD can benefit from CBT for anxiety. Notably, teens with lower expressive language showed greater improvements in overall anxiety, indicating they should not be excluded from adapted CBT programs. These findings challenge the belief that CBT is inaccessible for individuals with IDD. Limitations and future directions will be discussed.