Childhood Anxiety: an Early Predictor of Mood Disorders in Offspring of Bipolar Parents

Background: Anxiety disorders are common among the offspring of parents with bipolar disorder (BD). This study investigated the nature of the association between anxiety disorders and mood disorders in a prospectively studied high-risk cohort.

Methods: High-risk offspring were identified from families in which one parent had confirmed BD based on SADS-L interviews and best estimate diagnostic procedures. All agreeable offspring aged 8-25 years were enrolled in a longitudinal study involving repeated KSADS-PL format clinical assessments. Control (C) offspring from families in which neither parent met lifetime criteria for a psychiatric disorder were similarly assessed. All DSM-IV diagnoses in the offspring were confirmed on blind consensus review. Cumulative incidence and adjusted Cox Proportional Hazards models were used to calculate the risk of anxiety disorders and the predictive association with mood disorders.

Results: The cumulative incidence of anxiety disorders was higher (23.40% vs. 10.42%; HR=2.136; p=.0382) and occurred earlier (9.79 vs. 14.84 years; p=.0125) in high-risk compared to C offspring. In high-risk offspring generalized anxiety disorders (GAD) followed by social phobia were the most incident anxiety subtypes; while high emotionality (HR 1.111; p=.0096) and shyness (HR 1.144; p=.0053) increased the risk of anxiety disorders. Anxiety disorders increased the adjusted risk of mood disorders (HR 2.166; p=.0004), on average 8.49 years later (SD 5.97).

Limitations: The cumulative incidence of BD is relatively low, as the cohort is still in the period of risk.

Conclusions: Findings highlight the need for longitudinal surveillance of symptomatic high-risk children and suggest anxiety disorders are an important early intervention target.