Relationship of emotion recognition skills of children with attention deficit hyperactivity disorder and serum cytokine levels

Objective: Emotion recognition difficulties and impaired social responsiveness in children with ADHD may adversely affect the course of the disease and lead to loss of function in many areas. In this study, we aimed to contribute to the determination of biological processes that may be associated with emotion recognition difficulties and social impairment by examining the relationship between serum cytokine levels and emotion recognition and social responsiveness in children aged 6-12 years with ADHD. Methods: The research was conducted between September 2022 and May 2023 at the Department of Child and Adolescent Psychiatry, Faculty of Medicine, Karadeniz Technical University. Among the children diagnosed with ADHD according to clinical evaluation, DSM-5 diagnostic criteria and Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children Present and Lifetime Version-Turkish Adaptation (K-SADS-PL-T), 48 people who accepted the study and met the eligibility criteria were included in the study as the case group; 40 people matched with these patients in terms of gender and age were included as the control group. The child face, adult face and adult posture subtests of the Diagnostic Analysis of Nonverbal Expressions-2 (DANVA2) test were used to evaluate the participants' emotion recognition skills; the Social Responsiveness Scale (SRS) was used to evaluate their social responsiveness; and the Turgay DSM-IV-Based Child and Adolescent Behavioral Disorders Screening and Rating Scale (T-DSM-IV-S) was used to ADHD symptom severity. Serum IL (Interleukin)-1Beta, IL-6, IL-8, IL-17 levels of the participants in the case and control groups were measured with commercial ELISA kits. Results: Of all participants, 81.8% (n=72) were male and 18.2% (n=16) were female and the mean age was calculated as 8.67±1.7 years. No significant difference was found between the case and control groups in terms of age and gender. When compared with the control group, the total SRS score of the case group was found to be significantly higher (p< .001). The case group performed worse than the control group in the DANVA2 test, which included child face (p= .001), adult face (p= .04) and adult posture (p= .01) subtests. When the case group was grouped according to comorbidities and compared in terms of DANVA2 total test score, the ADHD group with oppositional defiant disorder scored significantly lower than the pure ADHD group (p< .001). The case group showed lower performance in recognising happy (p= .001) and fearful (p= .047) emotional expressions than the control group. ADHD symptom severity was positively correlated with SRS total score (r=0.495, p< .001). Serum IL-6 levels of the case group were found to be significantly higher compared to the control group (p= .008). The regression model including ADHD symptom severity and serum IL-6 levels in determining the predictors of social responsiveness in the case group was found significant (p< .001). According to this model, serum IL-6 levels were found to be a significant variable in predicting social responsiveness in children with ADHD (β=-0.044, p= .04). Conclusion: The fact that emotion recognition difficulties and impairment in social responsiveness are higher in some children with ADHD compared to healthy controls, and that serum IL-6 level is a significant variable in predicting social responsiveness, draws attention in terms of providing new ideas about the potential biological processes underlying this impairment. Keywords: Attention deficit hyperactivity disorder, social cognition, emotion recognition, cytokine