Symptom network connectivity in patients with anxiety disorders with and without comorbid depressive disorder

BACKGROUND: Comorbidity between anxiety and depression is highly prevalent. Network theory offers a psychometric approach to studying psychopathology and comorbidity. This study investigated connectivity between anxiety and depressive symptoms in a transdiagnostic, outpatient anxiety sample using network analysis. METHOD: In a secondary analysis of baseline data from an RCT, enrolling patients with agoraphobia, agoraphobia with panic disorder, panic disorder, social phobia or ≥ 2 specific phobias as a primary diagnosis, a regularized partial correlation network was estimated to examine symptom connectivity and (bridge) strength centrality. Subsequently, the sample was divided into two subgroups: individuals with and without comorbid depressive disorders. We first compared anxiety symptom severity between groups, followed by the estimation of separate networks to compare network structure, edge strength, and global strength. RESULTS: Out of 726 patients, 46.56% presented a comorbid depressive disorder. Symptoms with highest strength centrality in the full-sample network were worthlessness, loss of energy and feeling burdened due to anxiety-related problems. Next to the symptom agitation, the latter also emerged as the strongest bridge symptom. The comorbid group showed higher anxiety severity, while networks did not differ in any examined measure. CONCLUSIONS: Symptoms with highest strength centrality matched ICD-10 main criteria for depression and a wide range of anxiety disorders, supporting strength centrality as a clinically meaningful marker. The determination of bridge strength may highlight clinically relevant candidates for future transdiagnostic investigations. Contrary to theoretical assumptions of the network approach, higher anxiety symptom severity in the comorbid group was not accompanied by increased network density.