Familial aggregation of anxiety disorder subtypes and anxious temperament in the NIMH Family Study of Affective Spectrum Disorders.

Background: Evidence from family and twin studies suggests that mood and anxiety disorders, and related temperamental factors may share common etiologic factors. We examine the familial aggregation and coaggregation of anxiety disorder subtypes and anxiety-related temperamental traits, and their association with mood disorders.

Methods: A total of 477 probands and 549 first-degree adult relatives from a large community based family study of affective spectrum disorders completed semi-structured diagnostic interviews and self-reported assessments of temperamental traits including: negative affectivity on the 'Positive and Negative Affect Schedule' (PANAS), neuroticism anxiety on the 'Zuckerman-Kuhlman Personality Questionnaire' (ZKPQ), and anxiety sensitivity on the 'Anxiety Sensitivity Index' (ASI).

Results: The anxiety-related temperamental traits of negative affectivity, neuroticism anxiety and anxiety sensitivity had significant familial specificity, even after controlling for comorbid mood and anxiety disorders in probands and relatives. Yet, these traits in probands did not predict anxiety disorders in relatives. Although some anxiety subtypes were familial, there were no longer familial links between anxiety disorder subtypes (generalized anxiety disorder, social anxiety or panic disorder) after controlling for mood disorder subtypes in probands and relatives.

Limitations: Cross-sectional interviews were used to estimate disorders, and self-report measures were used for temperamental traits.

Conclusions: These results confirm previous research regarding familial overlap between anxiety subtypes and mood disorders, however their shared liability cannot be fully explained by anxiety-related temperamental traits. These findings suggest that anxiety-related temperamental traits may indicate a vulnerability for mood and anxiety disorders or a potential consequence of these conditions.