[Sleep and neurodevelopment: a timely subject].

Sleep problems are very common in children with autism and ADHD, affecting 30-80% of these children. Children with autism often have trouble making melatonin (a sleep hormone), leading to difficulty falling asleep, staying asleep, and getting enough sleep overall. Children with ADHD commonly have delayed sleep patterns and restless legs. Poor sleep makes the main symptoms of both conditions worse.

Treating sleep problems with behavioral strategies or melatonin can significantly help improve children's daily functioning and quality of life.

This review examines the relationship between sleep disturbances and neurodevelopmental disorders (NDDs), focusing on autism spectrum disorder (ASD) and ADHD. Sleep problems affect 30-80% of individuals with NDDs. In ASD, reduced melatonin synthesis leads to sleep-onset and maintenance insomnia, plus shortened sleep duration. ADHD commonly presents with delayed sleep phase syndrome and restless legs syndrome.

Sleep disorders exacerbate core symptoms: worsening inattention, hyperactivity, and impulsivity in ADHD, and amplifying emotional regulation difficulties and behavioral disturbances in ASD. The review emphasizes that identifying and managing sleep disorders is essential for improving quality of life and reducing daytime symptoms, with behavioral and pharmacological interventions (particularly melatonin) showing significant efficacy.

Sleep assessment should be routine in neurodevelopmental disorder evaluations. Addressing sleep disturbances through behavioral interventions and melatonin supplementation may improve core symptoms and quality of life. A multidisciplinary approach integrating sleep management into comprehensive care plans is recommended for optimal outcomes.

As a narrative review, no systematic methodology or quality assessment of included studies is described. The abstract does not specify sample sizes, study designs, or effect sizes of the interventions mentioned, limiting assessment of evidence strength.

Neurodevelopmental disorders (NDDs) include a heterogeneous group of conditions characterized by an alteration of neurodevelopmental processes leading to a significant impact on the individual's personal, social, and/or academic functioning. Among the many comorbidities frequently associated with NDDs, sleep disturbances play a major role, affecting between 30% and 80% of concerned people. This article explores the various links between sleep and NDDs through a review of the scientific literature highlighting the most recent research in this area, with a particular focus on two neurodevelopmental disorders: autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). Sleep is an essential physiological process regulated by homeostatic and circadian mechanisms, playing a crucial role in brain maturation.

In children with ASD, a decrease in the activity of enzymes responsible for melatonin synthesis has been identified, leading to a melatonin production and secretion deficiency that is associated with sleep-wake cycle disturbances. As a result, autistic people suffer from sleep-onset insomnia, sleep-maintenance insomnia with particularly long nocturnal awakenings, and reduced total sleep duration. In ADHD, on the other hand, the most commonly observed sleep disorders include delayed sleep phase syndrome and restless legs syndrome, both responsible for sleep-onset insomnia. Due to its essential role in memory consolidation, emotional regulation, and attention, sleep directly influences an individual's cognitive and behavioral development.

Thus, sleep disorders in children with ADHD exacerbate inattention, hyperactivity and impulsivity, while in children with ASD, they amplify emotional regulation difficulties and behavioral disturbances. Identifying sleep disorders for their management in patients with NDDs is essential to improving their quality of life and reducing the severity of their daytime symptoms. Therapeutic interventions, whether behavioral or pharmacological - particularly melatonin administration - have shown significant efficacy. An integrated, multidisciplinary approach can optimize patient care and enhance their social and cognitive adaptation.

A better understanding of the interactions between sleep disorders and NDDs thus opens new avenues for improving strategies in the management of individuals with NDDs.