Positive and Negative Affect as Links Between Social Anxiety and Depression: Predicting Concurrent and Prospective Mood Symptoms in Unipolar and Bipolar Mood Disorders.

The co-occurrence of social anxiety and depression is associated with increased functional impairment and a more severe course of illness. Social anxiety disorder is unique among the anxiety disorders in sharing an affective profile with depression, characterized by low levels of positive affect (PA) and high levels of negative affect (NA). Yet it remains unclear how this shared affective profile contributes to the covariation of social anxiety and depressive symptoms. We examined whether self-reported PA and NA accounted for unique variance in the association between social anxiety and depressive symptoms across three groups (individuals with remitted bipolar disorder, type I [BD; n = 32], individuals with remitted major depressive disorder [MDD; n = 31], and nonpsychiatric controls [n = 30]) at baseline and follow-ups of 6 and 12 months. Low levels of PA, but not NA, accounted for unique variance in both concurrent and prospective associations between social anxiety and depression in the BD group; in contrast, high levels of NA, but not PA, accounted for unique variance in concurrent and prospective associations between social anxiety and depression in the MDD group. Limitations include that social anxiety and PA/NA were assessed concurrently and all measurement was self-report. Few individuals with MDD/BD met current diagnostic criteria for social anxiety disorder. There was some attrition at follow-up assessments. Results suggest that affective mechanisms may contribute to the high rates of co-occurrence of social anxiety and depression in both MDD and BD. Implications of the differential role of PA and NA in the relationship between social anxiety and depression in MDD and BD and considerations for treatment are discussed.