BDNF and depressive symptom measurement: Another group showed that three weeks of repeated intraperitoneal BHB administration ameliorated depressive behaviors in a mouse model of depression involving spatial restraint stress and dexamethasone administration, as BHB administration increased histone3‐lysine9‐β‐hydroxybutyrylation, leading to upregulated expression of brain‐derived neurotrophic factor (BDNF) 14.