PREP and Anxiety: Previous studies on prolyl oligopeptidase (POP), another oligopeptidase linked to proteostasis‐related disorders (Hannula et al. 2013; Svarcbahs et al. 2019; Walczewska‐Szewc et al. 2022; Eteläinen et al. 2023), have shown that POP deficiency in mice disrupts synaptic plasticity, reduces anxiety‐like behavior, and decreases body weight and brain volume (Höfling et al. 2016).