Direction of Dependence Between Specific Symptoms of Depression: A Non-Gaussian Approach

Psychopathology could arise from direct interactions between symptoms. Evidence suggests that the mechanisms underlying somatic and cognitive-affective symptoms of depression are different. The aim of this study was to explore dynamic associations among cognitive-affective depression criteria. We used distribution-based direction of dependence models, which estimate whether the presence of symptom A is more likely to depend on the presence of symptom B than vice versa. We analyzed six large samples of adults from the United States (N = 34,963) and conducted a simulation study to test the performance of the algorithm with ordinal variables and a second simulation study focusing on Type I error. Our results were consistent with the literature: Depressed mood and anhedonia were reactive to changes in other symptoms, whereas suicidality may reinforce other symptoms or reflect factors doing so. We discuss the results in the context of other empirical findings and theories of depression, reflect on the potential of these methods in psychopathology, and consider some practical implications.