Early childhood insomnia phenotypes and temperament: a theoretical review with clinical implications for precision assessment and treatment.

purposeThis theoretical review examines the clinical heterogeneity of early childhood insomnia and proposes a phenotype-based framework that integrates temperament into assessment and treatment planning in infants and preschool children (approximately 0-5 years). We focus on three clinically relevant presentations: (1) motor restlessness with fragmented sleep, (2) prolonged early-morning awakenings, and (3) sleep-maintenance insomnia with repeated awakenings frequently amplified by somatic triggers such as allergic symptoms.

methodsWe conducted a targeted PubMed/MEDLINE search for English-language literature published from 2006 through February 9, 2026. Search terms covered early childhood insomnia phenotypes, temperament/personality, hyperarousal and circadian factors, iron/dopamine-related motor restlessness, and allergic/histamine pathways. This review was designed as a targeted theoretical synthesis rather than a systematic review, with emphasis on clinically relevant pediatric studies, established insomnia frameworks, and mechanistic literature that could inform interpretation.

resultsAcross infancy and the preschool years, higher negative emotionality/affectivity is repeatedly associated with poorer sleep continuity, more night waking, and greater caregiver involvement at bedtime and during the night. A phenotype-based reading of the literature suggests that temperament may help explain why children with similar sleep complaints present differently and respond differently to treatment. Specifically, novelty seeking may increase bedtime "downshifting" difficulty and align with motor-restless insomnia presentations linked to dopamine/iron pathways; harm avoidance may increase vigilance, stress sensitivity, and hyperarousal relevant to early-morning-awakening insomnia; and allergic symptom burden may promote sleep-maintenance insomnia through histaminergic and noradrenergic arousal, with temperament shaping the child's appraisal of awakenings and the caregiver-child reinforcement cycle.

conclusionA temperament-informed, phenotype-guided approach may improve clinical evaluation, parent counseling, and treatment matching in early childhood insomnia while preserving behavioral strategies as first-line care. Prospective studies should test whether early temperament profiles moderate objective sleep trajectories and response to behavioral, circadian, allergy-focused, and iron-targeted adjunctive interventions. Current knowledge/review rationale Early childhood insomnia is clinically heterogeneous and cannot be fully understood within a child-behavior or parent-management framework alone. A targeted theoretical review allows integration of developmental sleep, temperament, neurobiological, and clinical literature to generate a phenotype-based model for assessment and treatment. Review impact A phenotype-based model that incorporates temperament may help organize clinical formulation, parent counseling, and treatment planning, while also generating testable hypotheses for future studies on behavioral, circadian, allergy-focused, and iron-targeted interventions.