The goal of the present study was to determine whether exposure to adversity in childhood contributes to a differential threshold at which stressful life events provoke depressive reactions in adolescence. In addition, to address empirical and conceptual questions about stress effects, the moderating effect of anxiety disorder history was also explored. This examination was conducted in a sample of 816 children of depressed and nondepressed mothers, who were followed from birth to age 15. Information on adversities experienced in childhood was collected both from mothers during the first five years of their youth's life and from the youths themselves at age 15, and included information on the mother's relationship with her partner, maternal psychopathology, as well as youth-reported abuse. Results indicated that youths with both greater exposure to adversity in childhood and a history of an anxiety disorder displayed increased depressive severity following low levels of episodic stress compared to youths with only one or neither of these risk factors. The results are speculated to reflect the possibility that early anxiety disorders associated with exposure to adversity in childhood may be a marker of dysregulated stress responses, and may help to account for the comorbidity of depression and anxiety in some individuals.

BACKGROUND Anxiety disorders tend to precede onset of comorbid depression. Several researchers have suggested a causal role for anxiety in promoting depressive episodes, but few studies have identified specific mechanisms. The current study proposes an interpersonal model of comorbidity, where anxiety disorders disrupt interpersonal functioning, which in turn elevates risk for depression. METHODS At age 15 (T1), 815 adolescents oversampled for maternal depression completed diagnostic interviews, social chronic stress interviews, and self-report measures. At age 20 (T2), participants repeated all measures and reported on self-perceived interpersonal problems. At approximately age 23 (T3), a subset of participants (n= 475) completed a self-report depressive symptoms measure. RESULTS Consistent with other samples, anxiety disorders largely preceded depressive disorders. Low sociability and interpersonal oversensitivity mediated the association between T1 social anxiety disorder and later depression (including T2 depressive diagnosis and T3 depressive symptoms), controlling for baseline. Interpersonal oversensitivity and social chronic stress similarly mediated the association between generalized anxiety disorder before age 15 and later depression. CONCLUSIONS Interpersonal dysfunction may be one mechanism through which anxiety disorders promote later depression, contributing to high comorbidity rates.

Individuals with a history of depression experience more stress that is dependent in part on their own actions. However, it is unclear whether stress generation is a unique feature of depression, or a universal process that is also present in other types of psychopathology, such as anxiety disorders. The current study addressed this issue by comparing adolescents with a history of “pure” (i.e., non-comorbid) depressive disorders, pure anxiety disorders, comorbid depression and anxiety, and no disorder, on their levels of dependent and independent stress. Results indicated that adolescents with pure depression experienced more dependent stress than adolescents with pure anxiety, and adolescents with any internalizing diagnosis experienced more dependent stress than controls. Further, adolescents with comorbid depression and anxiety reported the highest levels of stress generation. The results suggest that while stress generation may be more strongly associated with depression than anxiety in adolescence, it is not unique to depression.