PATHOPHYSIOLOGICAL SUBTYPES OF PAEDIATRIC INSOMNIA BASING ON FAMILIAL AND CLINICAL FEATURES

Introduction Paediatric insomnia is a complex combination of biological, circadian, neurodevelopmental and environmental variables. Recent studies emphasized the role of genetic factors in childhood insomnia, highlighting how not only insomnia familiarity plays a key role, but also familiarity for other medical disturbances (atopy, anaemia, martial deficiency, psychiatric disorders, etc). Based on the insomnia clinical presentations, several pathophysiological subtypes have been proposed, reflecting specific sleep problems, child disorders, and related family history. The aim of this study is to identify different clusters of clinical and familiar features to understand whether specific familiarities are more frequently related to selected paediatric insomnia phenotypes. Methods We retrospectively revised 424 medical records of children with insomnia admitted from January 2015 to October 2022 at the Child Neuropsychiatry Unit, Sant'Andrea Hospital, Rome. We collected demographic data, insomnia clinical features, medical and sleep family history. A cluster analysis was conducted using hierarchical and non-hierarchical methods to determine the best representative model and to test stability and replicability of the clusters. Results Three reproducible and stable groups were identified with significant differences (p<0.001) in the frequency of the following clinical and familiar features. Fist cluster (n.144) was characterized by children having insomnia starting after weaning (10.4%), a medical history of atopy (17.4%) or gastroesophageal reflux (12.5%). Second cluster (n.119) included children experiencing prolonged awakenings (29.4%), pavor (24.4%) or sleepwalking (3.4%). Third cluster (n.161) included children having an agitated sleep, characterized by hypermotility (63.4%) or RLS symptoms (11.2%), 51.6% of them had a delayed falling asleep, in addition to nocturnal awakenings. As regards the family history, the first cluster had a strong family history of allergies (87.5%) and the third cluster of RLS (30.4%) and iron deficiency (75.2%). Conclusions Our study supports the existence of distinct pathophysiological subtypes within paediatric insomnia, witnessed by diverse clinical presentations matching with specific medical and familiar history. We hypothesize that these insomnia subtypes may involve dysfunctions in neurotransmitter systems implicated in sleep regulation, such as serotonin, dopamine, and histamine. Recognizing these distinct phenotypes through a careful medical and familiar history may guide tailored treatment approaches for paediatric insomnia, revolutionizing the current management of children sleep problems.