Conjoint Effects of ASD Status and ADHD Symptom Severity on Inflated Social Self-Perception in Youth

Background:

Inflated self-perception, or positive illusory bias (PIB) is a common phenomenon in youth (Barry, 2011), particularly among those with ADHD (Owens et al., 2007; Emeh et al., 2014). PIB is associated with negative outcomes in individuals with ADHD including aggressive behavior, poor social functioning, and poor treatment response (Hoza et al., 2010; Mikami et al., 2010). Recent research suggests that PIB may also be evident in individuals with ASD (Lerner et al., 2012). Crucially, ADHD is highly comorbid with ASD, with up to 80% of individuals with ASD meeting criteria for ADHD (Rommelse et al., 2010). Due to the high rate of comorbidity, it is plausible that PIB in individuals with ASD is an artifact of their ADHD symptoms, rather than a unique phenomenon in ASD, or that ASD and ADHD confer additive influences. To date, no study has investigated this conjoint influence in PIB.

Objectives:

To investigate the relative contributions of ASD status and ADHD symptom severity on PIB in a large sample of youth with and without ASD.

Methods:

Parents completed a developmental history questionnaire on 142 youth (102 male) ages 7-17 (M_age = 12.51, SD_age = 2.46) which included information on diagnoses. Adolescents and their parents completed the Social Skills Improvement System (SSIS; Gresham & Elliot, 2008), a measure of social skills. ADHD symptom severity was measured using the parent-reported ADHD Combined-type severity score from the Child & Adolescent Symptom Inventory (CASI-5; Gadow & Sprafkin, 2013; Table 1). Effects were also examined for Hyperactive- and Inattentive-type ADHD. PIB was measured using difference scores on the SSIS (see Table 1). Hierarchical multiple regression was used to predict PIB based on ASD status (to ascertain the relationship of ASD diagnosis to PIB), ADHD severity (to determine its relative influence on PIB), and their interaction (to determine if any ADHD severity effect is unique to those with ASD), controlling for ADHD status (to isolate symptom severity and clinical diagnosis effects).

Results:

ASD status predicted PIB (Table 2). After controlling for ASD status, ADHD severity predicted PIB, and ASD status no longer predicted PIB (Table 2). This effect held after controlling for ADHD status and the ASD status x ADHD severity interaction. Effects did not differ by ADHD symptom type.

Conclusions:

This is the first study to examine the conjoint effect of ASD status and ADHD symptom severity on PIB. While ASD status predicted PIB, this effect was reduced when ADHD severity (itself a predictor of PIB) was modeled. This was neither attributable to ADHD diagnosis, nor specific to youth with ASD. Thus, results suggest that, in a sample of youth with and without ASD and ADHD, while ASD does confer elevated PIB, this effect is partially accounted for by ADHD symptom severity regardless of ASD status. This suggests the presence of shared additive (but not multiplicative) influence of ASD status and ADHD symptom severity on social self-perception. Given the high rate of ADHD symptoms in ASD populations, this helps explain how and when PIB manifests in youth with ASD.