(PS4-54) Negative Repetitive Thinking as a Potential Treatment Target for Internalizing Symptoms in Autistic Adults: Stability and Predictive Validity in Short-term Longitudinal Data

Background: Perseverative thinking is a common feature of autism. Given that negative repetitive thinking (NRT) is linked to depression, anxiety, and other poor health outcomes in the general population (Ehring & Watkins, 2008; Sansone & Sansone, 2012), NRT may be a strong candidate mechanism to explain high lifetime rates of depression (27-47%) and anxiety (35-50%) among autistic adults (Hollocks et al., 2019). Previous research has shown that NRT is indeed elevated in autistic samples over non-autistic comparisons (Gotham et al., 2018) and is associated with greater autistic traits within transdiagnostic samples (Keenan et al., 2018). The current study aimed to explore whether, in short-term longitudinal data from autistic adults, NRT would: (1) have moderate levels of stability over time, 2) be positively correlated with depression scores within timepoints, and 3) have predictive validity for future depression scores over and above current depression and neuroticism.

Methods: 303 autistic adults aged 18-60 were recruited from the Simons Foundation Powering Autism Research for Knowledge (SPARK) cohort. At three timepoints across 3-4 months, NRT was measured using the novel Inventory of Negative Repetitive Thinking (INeRT); depression was measured using the AASPIRE–Revised Patient Health Questionnaire-9 (PHQ-9-R). Intraclass correlation coefficients (ICC), partial correlations, and linear regression models were used to assess NRT stability and association with synchronous and future depression scores, respectively.

Results: NRT was highly stable across all three timepoints (ICC = 0.83). When controlling for neuroticism (Big Five Inventory-2 neuroticism score), greater NRT was associated with greater depression scores at all timepoints (r_p = 0.45 for each). Controlling for Time 1 depression, Time 1 INeRT scores significantly predicted depression scores at Time 2 (β_Std = 0.11, 95% CI [0.01, 0.20], p < .001) and Time 3 (β_Std = 0.12, 95% CI [0.01, 0.24], p < .001).

 




Conclusion: In the autistic adult population, NRT (as measured by the INeRT) represents a temporally-stable cognitive trait that prospectively predicts future depressive symptoms over and above general neuroticism. These data suggest NRT could potentially be a cognitive target for intervention on depression in autistic adults. Future experimental work is necessary to demonstrate whether interventions targeting NRT as an active ingredient (e.g., rumination-focused cognitive-behavioral therapy) can provide disproportionate benefit for the depressed autistic population.