Besides behavioral changes, the LH paradigm has also shown to be able to alter psychophysiological functions in humans and non-human animals, such as changes in hypothalamic-pituitary-adrenal (HPA) axis activities [14] and sleep disturbance [15], both of which resemble human depression characteristics and thus contribute to the face validity of the LH model. Here, PLOD1 is linked to depressive symptom measurement.