BDNF and depressive symptom measurement: Another study suggested that the expression of brain derived neurotrophic factor (BDNF) and growth associated protein 43 (GAP‐43) in the hypothalamus was closely related to CRH in depression patients, and administration of CRH receptor antagonist could effectively downregulate the content of BDNF and GAP‐43, and reversed the depression‐like behaviors of animals (Dai, Zhang, & Chen, 2015).