VGF and depressive symptom measurement: Several types of VGF-derived peptides have been detected in the rat brain, bovine pituitary and human cerebrospinal fluid [32], [33], [34], [35], and these peptides possess multiple biological activities, autonomic activation, anti-depression, enhancement in synaptic plasticity, penile erection and increases in energy expenditure [11], [36], [37], [38].