Quand penser à l’existence d’un trouble spécifique du développement et des apprentissages associé au TDAH de l’enfant ?

Abstract

After the initial recommendations in 2014 on child attention deficit hyperactivity disorder (ADHD) published by the French Haute Autorité de santé (HAS), followed in 2018 by those devoted to specific learning and developmental disorders, and the new recommendations on child ADHD published in the third quarter of 2024 by the HAS, the issue of comorbidities between ADHD and other neurodevelopmental disorders remains a daily challenge for both families and professionals. This work therefore suggests that professionals who have suspected or diagnosed ADHD in a child or adolescent broaden their consideration, particularly concerning specific developmental and learning disorders that may be associated. They should rely on already available information, particularly from schools, and on screening tools accessible to primary and secondary care physicians before prescribing any additional assessments. Neurodevelopmental disorders include a large variety of conditions involving ADHD, motor disorders (among them developmental coordination disorder [DCD]), language and communication disorders (among them specific language disorder [SLD]), specific learning disorders (SLD) (written language both on the receptive and expressive side and mathematical disorders), autism spectrum disorders (ASD), and intellectual development disorder. We propose herein a brief description of these potential comorbid conditions, together with alert signs, which might give clues towards a diagnostic procedure of associated troubles. Moreover, comorbidities are often potential differential diagnosis. We therefore propose in our publication the tables published by the French HAS to help professionals to be aware of these conditions, with alert signs. Prevalence of these comorbidities benefit from our preliminary but exhaustive data from Parcours de Santé TSLA Occitanie on the prevalence of ADHD among complex neurodevelopmental disorders (NDD) with an estimation of more than 80% of concerned children and adolescent being eligible to a diagnosis of ADHD, representing an incidence of 5.6% between age 6 to 15. Among diagnosed ADHD children, comorbidities remain the rule, with specific learning disorders involving reading and spelling (dyslexia/dysorthographia): 46 to 62%, followed by developmental disorders: 41%, developmental language disorders: 24%, and specific learning disorders of mathematical abilities: 17%. This high-level of comorbidities confirms the need for each child to benefit from a multidisciplinary evaluation in various areas of development, particularly to detect secondary difficulties in learning (written language and math) or development (language, motricity), which might be masked by significant behavioural difficulties, or more subtly by pure inattention forms with primarily academic impact. Other comorbidities also need to be investigated, both towards social abilities, and secondary emotional consequences or comorbidities of ADHD including anxiety and depression. Our work also reviews data from literature about the conceptual framework between comorbidity and cause/consequence relationships, within a more comprehensive developmental perspective of various cognitive functions.