BACKGROUND: Sleep problems are linked to schizophrenia or bipolar disorder and often precede the onset of manifest illness. Psychotic experiences and mental disorders during childhood are risk factors for later development of schizophrenia and bipolar disorder. This study investigated whether nightmares, prolonged sleep latency, and nocturnal awakenings are associated with psychotic experiences and mental disorder in children at familial high risk of schizophrenia (FHR-SZ) or bipolar disorder (FHR-BP) and population-based controls (controls).
METHOD: The study included 447 eleven-twelve-year-old children: 170 at FHR-SZ, 103 at FHR-BP, and 174 controls. Primary caregivers of the children provided information about nightmares, sleep latency, and nocturnal awakenings. Psychotic experiences and mental disorders were assessed with the semi-structured interview, The Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children - present and lifetime version.
RESULTS: Children with psychotic experiences had significantly higher odds of nightmares, prolonged sleep latency, and nocturnal awakenings, but only the association between psychotic experiences and nocturnal awakenings remained significant after adjustment for mental disorders. Children with mental disorder had significantly higher odds of nightmares, prolonged sleep latency and nocturnal awakenings. Associations between sleep problems and psychotic experiences and mental disorders were non-differential across familial risk-groups.
CONCLUSIONS: Nightmares, prolonged sleep latency, and nocturnal awakening are associated with psychotic experiences and mental disorders in children at FHR-SZ and FHR-BP and controls. Sleep problems should be assessed in child and adolescent mental health services e.g. through anamnestic interviews or questionnaires. This may provide useful clinical information on an otherwise unrecognized marker of risk for mental health problems.
