Differences in the motor profiles of children and adolescents with ADHD in a clinically referred outpatient sample

Although the co-occurrence of ADHD and motor deficits is well documented, it remains unclear which of the clinical presentations of ADHD (ADHD-PI: predominantly inattentive, ADHD-HI: predominantly hyperactive-impulsive, ADHD-C: combined) are associated with different motor deficits (fine motor, gross motor, combined). In this study, ADHD symptoms and motor skills were assessed as part of routine clinical evaluations in children and adolescents who were referred primarily due to suspected ADHD to an outpatient clinic for child and adolescent psychiatry (N = 419, 100 female, aged 4.22 to 16.82 years). The co-occurrence of ADHD-symptoms and different motor deficits was investigated using a categorical and a continuous approach, the former with odds ratios and Fisher's exact tests, the latter with latent profile analyses and Welch's-ANOVA. The results indicated that about 60% demonstrated at least one motor deficit. Girls were more likely than boys to exceed the threshold for ADHD-C symptoms, whereas the opposite pattern was observed in ADHD-HI. Beyond gender, there were no differences in overall or specific motor deficits between clinical presentations of ADHD. However, girls with ADHD-C were less likely to demonstrate overall motor deficits than girls with other clinical presentations of ADHD. Boys with ADHD-C showed motor deficits even more often than girls with ADHD-C. The results of the dimensional approach indicated that the three-profile solution, despite showing the second-best statistical fit, represented a stronger conceptual match with the DSM-5 classification in terms of clinical relevance and largely confirmed the findings of the categorical approach. In conclusion, only few gender-specific differences in motor deficits were identified across the distinct clinical presentations of ADHD, while is cannot be excluded that referral bias influenced the results. The present findings emphasise the importance of a comprehensive assessment of motor skills in children and adolescents with ADHD, regardless of gender and clinical presentations of ADHD.