Abstract
OBJECTIVE: To examine the relationship between blood pressure and depressive disorder in children and adolescents at high risk for depression. DESIGN: Multisample longitudinal design including a prospective longitudinal three-wave high-risk study of offspring of parents with recurrent depression and an on-going birth cohort for replication. SETTING: Community-based studies. PARTICIPANTS: High-risk sample includes 281 families where children were aged 9-17 years at baseline and 10-19 years at the final data point. Replication cohort includes 4830 families where children were aged 11-14 years at baseline and 14-17 years at follow-up and a high-risk subsample of 612 offspring with mothers that had reported recurrent depression. MAIN OUTCOME MEASURES: The new-onset of Diagnostic and Statistical Manual of Mental Disorder, fourth edition defined depressive disorder in the offspring using established research diagnostic assessments-the Child and Adolescent Psychiatric Assessment in the high-risk sample and the Development and Wellbeing Assessment in the replication sample. RESULTS: Blood pressure was standardised for age and gender to create SD scores and child's weight was statistically controlled in all analyses. In the high-risk sample, lower systolic blood pressure at wave 1 significantly predicted new-onset depressive disorder in children (OR=0.65, 95% CI 0.44 to 0.96; p=0.029) but diastolic blood pressure did not. Depressive disorder at wave 1 did not predict systolic blood pressure at wave 3. A significant association between lower systolic blood pressure and future depression was also found in the replication cohort in the second subset of high-risk children whose mothers had experienced recurrent depression in the past. CONCLUSIONS: Lower systolic blood pressure predicts new-onset depressive disorder in the offspring of parents with depression. Further studies are needed to investigate how this association arises.