RESUMO
Background: Understanding the evolution of circadian rhythm dysfunction and psychopathology in the high-risk population has important implications for the prevention of bipolar disorder. Nevertheless, some of the previous studies on the emergence of psychopathologies and circadian dysfunction among high-risk populations were inconsistent and limited. Aims: To examine the prevalence rates of sleep and circadian dysfunctions, mental disorders and their symptoms in the offspring of parents with (O-BD) and without bipolar disorder (O-control). Methods: The study included 191 O-BD and 202 O-control subjects aged 6-21 years from the Greater Bay Area, China. The diagnoses and symptoms of sleep/circadian rhythm and mental disorders were assessed by the Diagnostic Interview for Sleep Patterns and Disorders, and the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version, respectively. Generalised estimating equations and shared frailty proportional hazards models of survival analysis were applied to compare the outcomes in the offspring. Results: Adjusting for age, sex and region of recruitment, there was a significantly higher risk of delayed sleep phase symptoms (9.55% vs 2.58%, adjusted OR: 4.04) in O-BD than in O-control. O-BD had a nearly fivefold higher risk of mood disorders (11.70% vs 3.47%, adjusted OR: 4.68) and social anxiety (6.28% vs 1.49%, adjusted OR: 4.70), a fourfold higher risk of depressive disorders (11.17% vs 3.47%, adjusted OR: 3.99) and a threefold higher risk of mood symptoms (20.74% vs 10.40%, adjusted OR: 2.59) than O-control. Subgroup analysis revealed that O-BD children (aged under 12 years) had a nearly 2-fold higher risk of any mental and behavioural symptoms than O-control, while there was a nearly 4-fold higher risk of delayed sleep phase symptoms, a 7.5-fold higher risk of social anxiety and a 3-fold higher risk of mood symptoms in O-BD adolescents (aged 12 years and over). Conclusions: There was an increase in delayed sleep phase symptoms in O-BD adolescents compared with their control counterparts, confirming the central role of circadian rhythm dysfunction in bipolar disorder. The findings of the specific age-related and stage-related developmental patterns of psychopathologies and circadian dysfunction in children and adolescent offspring of parents with bipolar disorder paved the way to develop specific and early clinical intervention and prevention strategies. Trial registration number: NCT03656302.
RESUMO
BACKGROUND: Circadian dysregulation has long been thought to be a key component in the pathophysiology of bipolar disorder (BD). However, it remains unclear whether this dysregulation constitutes a risk factor, manifestation, or consequence of BD. This study aimed to compare dim light melatonin secretion patterns between unaffected offspring of parents with BD (OBD) and offspring of control parents (OCP). METHODS: This case-control study included unaffected OBD (mean age 14.0 years; male 50.0 %) and age- and sex-matched OCP (mean age 13.0 years; male: 43.5 %). Seventeen saliva samples were collected in dim light conditions. Dim light melatonin onset (DLMO), phase angles, and area under the curve (AUC) were calculated. RESULTS: 185 saliva samples from 12 OBD (n = 12) and 741 from OCP (n = 46) were collected. Unaffected OBD had a significant lower nocturnal melatonin level (14.8 ± 4.6 vs. 20.3 ± 11.7 pg/mL) and a smaller melatonin AUC within two hours after DLMO (35.5 ± 11.3 vs. 44.6 ± 18.1 pg/mL) but a significant larger phase angle between DLMO and sleep onset (2.2 ± 1.0 vs. 1.4 ± 1.2 h) than OCP. There was no significant between-group difference in DLMO. The graphic illustrations showed a considerably flattened melatonin secretion in unaffected OBD. LIMITATIONS: The main limitations include lack of 24-h dim melatonin secretion measurement, large age range of participants, and small sample size. CONCLUSIONS: These findings suggest that unaffected OBD already presented with circadian rhythm dysregulations. Future investigations are needed to clarify the role of abnormal melatonin secretion in the onset of BD.
