Construction and validation of a machine learning-based nomogram model for predicting pneumonia risk in patients with catatonia: a retrospective observational study - Wang, Yi-chao; He, Qian; Wu, Yue-jing; Zhang, Li; Wu, Sha; Fang, Xiao-jia; Jia, Shao-shen; Luo, Fu-gang (Frontiers in Psychiatry, 2025)