To establish a causal connection between apoptotic events and depression and/or anxiety-like behaviors in comorbid mice, we performed correlation analyses between the apoptotic parameters of TUNEL staining, caspase-3 levels and Bcl-2 levels in the hippocampus and frontal cortex and behavioral test parameters generated from OFT, TST and FST using the Spearman’s rank test. Here, CASP3 is linked to major depressive disorder.