No added cost: Emotion recognition in co‐occurring <scp>ADHD</scp> and <scp>ASD</scp>

OBJECTIVES: Facial emotion recognition (FER) is fundamental for social interaction, yet this ability is often impaired in attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD). While research has documented these difficulties, two key questions remain: Are these deficits specific to recognising emotions or do they reflect broader challenges in face processing? Does the increasingly documented co-occurrence of ADHD and ASD exacerbate these difficulties? METHODS: We compared emotion discrimination thresholds (EDT) in N = 92 participants aged 17-45 years (mean = 28.5, SD = 7.2), including 22 autistic-only, 24 ADHD-only, 22 co-occurring ADHD+ASD and 24 typically-developing individuals. We measured EDT with faces gradually changing from a neutral to an emotional expression (angry, fearful, happy or sad) and designed a non-emotional control task. Using eye tracking, we ruled out potential differences in visual attention to facial features between groups. RESULTS: We showed a specific disadvantage in emotion in the clinical groups, with increased EDT in all three clinical groups, with effect sizes ranging from .43 for co-occurring ADHD+ASD to .77 for autistic-only. Crucially, emotion recognition deficits were not amplified by the co-occurrence of ADHD and ASD, when considering performance in the control task. CONCLUSIONS: Our study possibly suggests equal mechanisms underlying reduced FER in ASD and ADHD. This mechanism should be identified to develop targeted interventions addressing social cognitive challenges in ASD and ADHD, improving social integration and well-being. Clinicians should recognise that FER difficulties are shared across both conditions, since a primary association with ASD may lead to unwarranted assumptions of ASD co-occurrence in ADHD.