Le trouble de l’attention avec ou sans hyperactivité est un trouble neurodéveloppemental sous-tendu par des déficits cognitifs. Le diagnostic différentiel reste complexe chez l’enfant. En effet, le déficit attentionnel, l’hyperactivité et l’impulsivité sont communs à d’autres pathologies et sont notamment retrouvés en phase prodromique de la schizophrénie infantile. À travers une revue de la littérature internationale, nous avons tenté d’extraire certaines spécificités comportementales, développementales et cognitives permettant de distinguer ces deux troubles de manière précoce. L’ensemble des données montre la difficulté à établir le diagnostic différentiel, au risque de proposer une intervention thérapeutique inadaptée. La distinction entre les deux troubles ne semble pouvoir se réaliser qu’à la condition de regrouper un ensemble d’indices autour d’épreuves projectives, d’un nombre restreint de tests cognitifs et d’échelles cliniques comme la CBCL et le K-SADS. Les investigations médicales et le recueil des antécédents familiaux favoriseraient également l’élaboration du diagnostic différentiel.

Attention-Deficit/Hyperactivity Disorder is a neurodevelopmental disease underlaid by cognitive deficits. Establishing an Attention-Deficit/Hyperactivity Disorder diagnosis in children is difficult, because attention symptoms, hyperactivity and impulsivity are common to several other pathologies like childhood-onset schizophrenia. Thus, Attention-Deficit/Hyperactivity Disorder can be considered in literature like a prodromal symptom of childhood-onset schizophrenia.

This paper is meant to show the complexity of the differential diagnosis of Attention-Deficit/Hyperactivity Disorder and childhood-onset schizophrenia in prodromal phase, two pathologies sharing symptomatic connections. By investigating their behavioral, developmental and cognitive similarities and dissimilarities, we bring to light specific indicators enabling to distinguish among them as part of a differential diagnostic approach.

The field's international literature has been critically reviewed using ScienceDirect, Google Scholar, PubMed and Cairn Info.

It seems difficult to isolate behavioral, developmental or cognitive indicators specific to each pathology. Furthermore, neuropsychological evaluations appear to provide little in favor of an easy discrimination between Attention-Deficit/Hyperactivity Disorder and childhood-onset schizophrenia. However, the combined use of some of the neuropsychological tests and projective testing, the use of CBCL and K-SADS questionnaires, or social cognitions investigations could provide valuable clues when establishing the differential diagnosis. Finally, psychopathological family antecedents and pediatric investigations could contribute to differentiate ADHD and childhood-onset schizophrenia.

Differential diagnosis between Attention-Deficit/Hyperactivity Disorder and childhood-onset schizophrenia in prodromal phase requires multiple investigations in the medical and psychological domains to avoid confusion.