Chronobiology in Paediatric Neurological and Neuropsychiatric Disorders: Harmonizing Care with Biological Clocks.

: Chronobiology has gained attention in the context of paediatric neurological and neuropsychiatric disorders, including migraine, epilepsy, autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and post-traumatic stress disorder (PTSD). Disruptions in circadian rhythms are associated with key symptoms such as sleep disturbances, mood dysregulation, and cognitive impairments, suggesting a potential for chronobiology-based therapeutic approaches. : This narrative review employs a systematic approach to identify relevant studies through searches of three major scientific databases, NCBI/PubMed, ScienceDirect, and Scopus, up to July 2024. We used a combination of broad and condition-specific keywords, such as "chronobiology", "biorhythm", "pediatric", "epilepsy", "ADHD", and "ASD", among others. Articles in English that focused on clinical features, treatments, or outcomes related to circadian rhythms in paediatric populations were included, while non-peer-reviewed articles and studies lacking original data were excluded. Rayyan software was used for article screening, removing duplicates, and facilitating consensus among independent reviewers. : A total of 87 studies were included in the analysis. Findings reveal a consistent pattern of circadian rhythm disruptions across the disorders examined. Specifically, dysregulation of melatonin and cortisol secretion is observed in children with ASD, ADHD, and PTSD, with altered circadian timing contributing to sleep disturbances and mood swings. Alterations in core clock genes (, , , and ) were also noted in children with epilepsy, which was linked to seizure frequency and timing. Chronotherapy approaches showed promise in managing these disruptions: melatonin supplementation improved sleep quality and reduced ADHD symptoms in some children, while light therapy proved effective in stabilizing sleep-wake cycles in ASD and ADHD patients. Additionally, behaviour-based interventions, such as the Early Start Denver Model, showed success in improving circadian alignment in children with ASD. : This review highlights the significant role of circadian rhythm disruptions in paediatric neurological and neuropsychiatric disorders, with direct implications for treatment. Chronobiology-based interventions, such as melatonin therapy, light exposure, and individualized behavioural therapies, offer potential for improving symptomatology and overall functioning. The integration of chronotherapy into clinical practice could provide a paradigm shift from symptom management to more targeted, rhythm-based treatments. Future research should focus on understanding the molecular mechanisms behind circadian disruptions in these disorders and exploring personalized chronotherapeutic approaches tailored to individual circadian patterns.