AbstractBackgroundThe purpose of this study was to investigate whether dependent personality and/or general personality dimensions might explain the strong relationships between separation anxiety disorder (Sep‐AD) and three other anxiety disorders (agoraphobia, panic disorder and social anxiety disorder) in individuals with obsessive compulsive disorder (OCD).MethodsUsing data from 509 adult participants collected during the OCD Collaborative Genetic Study, we used logistic regression models to evaluate the relationships between Sep‐AD, dependent personality score, general personality dimensions and three additional anxiety disorders.ResultsThe dependent personality score was strongly associated with Sep‐AD and the other anxiety disorders in models adjusted for age at interview, age at onset of OC symptoms and worst ever OCD severity score. Several general personality dimensions, especially neuroticism, extraversion and conscientiousness, were also related to Sep‐AD and the other anxiety disorders. Sep‐AD was not independently related to these anxiety disorders, in multivariate models including general personality and dependent personality disorder scores.ConclusionsThe results suggest that Sep‐AD in childhood and these other anxiety disorders in adulthood are consequences of dependent personality disorder (for agoraphobia and panic disorder) or introversion (for social phobia). It is unknown whether these results would be similar in a non‐OCD sample. Copyright © 2015 John Wiley & Sons, Ltd.