Relationships Between ASD/ADHD Symptoms and Abnormal Eating Behaviors in Children

Background: Some people with autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) symptoms also have eating disorders. An increasing number of studies have dealt with comorbidity of eating and developmental disorders. Anorexia nervosa overlaps with ASD (Iwasaki et al., 2014; Oldershaw et al., 2011), while binge eating behaviors are associated with ADHD (Nazar et al., 2014). It is important to recognize people with ASD and ADHD symptoms who have abnormal eating behaviors. Despite the correlation between ASD and ADHD, little previous research has investigated their connection to eating disorders at the same time. Therefore, it is necessary to consider ADHD symptoms as covariant. Furthermore, most previous studies investigated clinical groups. Thus, there is little research examining the relationship of ASD and ADHD symptoms with eating behaviors in the general population in Japan. 

Objectives: The present study investigated whether ASD and ADHD symptoms are related to abnormal eating behaviors in elementary and junior high school students in Japan.   

Methods: Participants were 4584 children from 4^th to 9^th grade students enrolled in all elementary and junior high schools of a single city. 2314 were boys and 2270 were girls. The children completed an eating behavior inventory that measured propensity of anorexia and bulimia (Ito et al., submitted). Their parents or caregivers completed two questionnaires: the Autism Spectrum Screening Questionnaire (ASSQ; Ehlers, Gillberg, & Wing, 1999) for ASD symptoms and the ADHD Rating Scale (ADHD-RS; Dupaul, Power, Anastopoulos, & Reid, 1998) for inattention/hyperactivity. To investigate the effect of ASD and ADHD symptoms on the propensity of anorexia and bulimia, polynominal regression analysis was conducted.  

Results: The analysis found that the linear effect of ASSQ  (β=.062, p=.011) and ADHD-RS (β=.086, p<.001) were significant regarding propensity of anorexia. In terms of propensity of bulimia, the liner and nonlinear (quadratic) effect of ASSQ (liner; β=.062, p=.017, nonlinear; β=-.057, p=.018) and the liner effect of ADHD-RS (β=.140, p<.001) were significant. (Fig.1) The other was not significant.  

Conclusions: First, both propensity of anorexia and bulimia are affected by ASD and ADHD symptoms. This relationship is supported by previous research, which refers to similar results in clinical cases. Second, propensity of bulimia is affected more by ADHD symptoms than by ASD symptoms. It is thought that aspects of ASD symptoms associated with poor social skills and those of ADHD symptoms associated with impulsivity may be associated with abnormal eating behaviors. These findings suggest that investigation of ASD and ADHD symptoms may lead to more appropriate treatment for people exhibiting abnormal eating behavior.