Relationship of behavioral inhibition to separation anxiety in a sample (N = 377) of adult individuals with mood and anxiety disorders

Background: Behavioral Inhibition (BI) is an early temperamental trait characterized by shyness, withdrawal, avoidance, uneasiness, and fear of unfamiliar situations, people, objects, and events. The DSM-5 refers to behavioral inhibition as a temperamental factor related to neurodevelopmental conditions in childhood, including attention deficit hyperactivity disorder, selective mutism, and specific phobias; and to its influence on adult anxiety disorders including social anxiety disorder, agoraphobia, and generalized anxiety disorder, but, interestingly, not separation anxiety disorder (SAD). However, there are phenomenological overlaps between BI and SAD. We aimed to explore whether there is a correlation between BI as an early temperamental trait and childhood or adult separation anxiety disorder.Methods: The study was conducted in 377 consecutive adults (mean age 40.2 +/- 12.4 years) outpatients with anxiety and mood disorders as the principal diagnosis, grouped on the presence/absence of a DSM-5 diagnosis of childhood or adult separation anxiety disorder. Separation anxiety was assessed by the Structured Clinical Interview for Separation Anxiety (SCI-SAS) and the Adult Separation Anxiety Checklist (ASA27). Behavioral inhibition was assessed by the Retrospective Self-Report of Inhibition (RSRI). Results: The four comparison groups included: 1) 168 patients without childhood or adult SAD, 2) 81 with adult SAD, 3) 97 with both adult SAD and childhood SAD, and 4) 31 with childhood SAD only. The group with both adult and childhood SAD had the highest scores on RSRI total and sub-scale scores. Both groups with adult SAD had significantly higher RSRI scores than the group with only childhood SAD or without SAD. Significant bivariate correlations were found between ASA-27 scores and RSRI scores. Correlations between RSRI scores and measures of anxiety and depressive symptoms were significantly weaker than those on the ASA-27. Regression analyses showed a significant predictive value of RSRI scores on ASA-27 total score, but not of age of onset of SAD.Conclusions: BI has an onset in the very first years of life and may represent a potential developmental endophenotype for later anxiety disorders. Our findings indicate that BI and separation anxiety are connected in individuals with affective and anxiety disorders. This may have important clinical and therapeutic implications for preventive interventions.