Objectives: The current study examined dimensional measures of behaviour in four categorically defined groups with ASD, ADHD, ADHD+ASD and controls, to assess whether emotion recognition abilities were related to ASD and ADHD traits within and across disorders.
Methods: 113 males between the ages of 7 and 16 took part in the study. Included were individuals who, according to the DSM-IV, fulfilled the diagnosis of an ADHD (n=33) or ASD with (n=39) and without comorbid ADHD symptoms (n=17) and healthy controls (n=24) with an IQ>70. Both SCQ and Conners questionnaire scores provided a measure of parent-reported ASD and ADHD traits for all participants. Facial affect recognition was assessed using labelling and same/different discrimination computer tasks, with negative emotions (sad, angry, fear, disgust) from the Facial Expression of Emotion: Stimuli and Tests (FEEST) at three different intensities (25%. 50%, 75%).
Results: Correlational analysis using bias corrected scores across the whole sample revealed that fewer ASD traits were associated with more accurate performance on the labelling task (r=-.29, p=.001), but not the discrimination task (p≥.10). The same pattern of results was shown for both inattentive traits (rs=-.21,p=.02) and hyperactive/impulsive traits (rs=-.25, p=.01). However, after controlling for FSIQ only the association between ASD traits and emotion labelling ability remained significant.
Conclusions: The current results suggest that the correlations between emotion recognition performance and ADHD traits is dependent on IQ, whereas ASD traits are associated with performance on facial affect recognition tasks even after controlling for IQ. Overall, the findings support an association between ASD traits and emotion labelling abilities which may suggest a fundamental problem in identifying and processing emotion, independent of general cognitive ability.