Parental report-based assessment of sleep problems and mental health in an unreferred cohort of children with a fragile X premutation.

INTRODUCTION

Individuals with a fragile X premutation (PM) are at an increased risk for a variety of physical and mental health conditions, including sleep problems. Sleep problems in children in the general population have been shown to adversely affect development, cognition, behavior, and mood. Because information on the impact of sleep problems in children with a PM is limited, this study aimed to explore the extent of sleep problems in an unreferred cohort of children with a PM and with no PM (NP) and the relationship between sleep and mental health.

METHODS

Using the parent-completed Child Behavior Checklist, sleep and mental health were assessed across two distinct study samples. First, a cross-sectional preschool cohort (n = 324; ages 3-5 years) was used to identify early associations and CGG-moderated effects. Second, a longitudinal cohort (n = 128) was assessed at Time 1 (3-7 years) and Time 2 (8-13 years) to examine cross-sectional and longitudinal associations of sleep and mental health outcomes.

RESULTS

Females with a PM exhibited significantly more sleep problems than females with NP at ages 3-5 years. In the preschool cohort, CGG repeat size moderated the relationship between sleep and mental health in a sex- and symptom-specific manner. Longitudinal trajectories differed by PM status: for children with NP, early sleep problems appear stable and predict later sleep outcomes. In contrast, for children with a PM, later sleep problems appear emergent and were associated with concurrent mental health symptoms independent of earlier sleep difficulties.

DISCUSSION: The results demonstrate that females with a PM are more likely than females with NP to experience sleep problems at young ages, and the relationship between sleep and mental health in children with a PM is moderated by CGG repeat size. Children with a PM appear to follow a unique developmental pathway characterized by longitudinal trajectories that diverge from those of children with NP, suggesting different underlying mechanisms.