Hierarchical structure of emotional disorders: From individual symptoms to the spectrum

Classification of emotional disorders faces challenges of within-disorder heterogeneity and between-disorder comorbidity. The current study addressed these issues by analyzing all emotional disorder symptoms to identify homogeneous dimensions that characterize this domain. These dimensions were, in turn, used to define coherent syndromes and higher order factors. All of the emotional disorder symptoms specified in diagnostic manuals were assessed by interview in 2 treatment-seeking samples (N = 426 and 305), alongside clinical diagnoses and functioning measures. Exploratory and confirmatory factor analyses were employed to elucidate replicable lower and higher order structures. We found 31 homogenous symptom dimensions that clustered, at different levels of generality, into 8 syndromes (Vegetative Symptoms, Cognitive Depression, Posttraumatic Stress Disorder, Panic, Social Anxiety, Phobia, Obsessive-Compulsive Disorder [OCD], and Mania), 3 subfactors (Distress, Fear, and OCD/Mania), and a single Internalizing spectrum. This structure replicated in both samples. Identified dimensions showed considerable convergence with categorical diagnoses, but provided more information about global functioning than diagnoses. Overall, current results propose a novel comprehensive description of the lower order structure of emotional disorders. The empirical syndromes generally paralleled disorders listed in diagnostic manuals, although several differences were notable. The higher order results also confirmed previously reported Distress, Fear, and Mania subfactors of the Internalizing spectrum using homogeneous dimensional markers. Taken together, results highlight a bottom-up approach to constructing an empirical nosology that does not rely on analysis of diagnostic categories. The resulting hierarchical system can be used clinically and to facilitate research on the pathophysiology of emotional disorders, which, in turn, can inform intervention and prevention.