Unraveling the distinction between depression and anxiety: A machine learning exploration of causal relationships

Depression and anxiety, prevalent coexisting mood disorders, pose a clinical challenge in accurate differentiation, hindering effective healthcare interventions. This research addressed this gap by employing a streamlined Symptom Checklist 90 (SCL-90) designed to minimize patient response burden. Utilizing machine learning algorithms, the study sought to construct classification models capable of distinguishing between depression and anxiety. The study included 4,262 individuals currently experiencing depression alone (n=2,998), anxiety alone (n=716), or both depression and anxiety (n=548). Counterfactual diagnosis was used to construct a causal network on the dataset. Employing a causal network, the SCL-90 was simplified. Items that have causality with only depression, only anxiety and both depression and anxiety were selected, and these streamlined items served as input features for four distinct machine learning algorithms, facilitating the creation of classification models for distinguishing depression and anxiety. Cross-validation demonstrated the performance of the classification models with the following metrics: (1) K-nearest neighbors (AUC = 0.924, Acc = 92.81%); (2) support vector machine (AUC = 0.937, Acc = 94.38%); (3) random forest (AUC = 0.918, Acc = 94.38%); and (4) adaptive boosting (AUC = 0.882, Acc = 94.38%). Notably, the support vector machine excelled, with the highest AUC and superior accuracy. Incorporating the simplified SCL-90 and machine learning presents a promising, efficient, and cost-effective tool for the precise identification of depression and anxiety.