The current study was conducted to investigate the effect of unpredictable chronic mild stress as a model of depression on the physiological and neurochemical parameters of male swiss mice. Twenty- Five adult male Swiss albino mice were housed in either control group or unpredictable chronic mild stress (UCMS) group that was exposed to different physical
stressors for 8 weeks. Plasma corticosterone and brain stem levels of dopamine and serotonin (5-OH) were measured. UCMS mice displayed an increase in the plasma corticosterone concentration and lower levels of both brain stem dopamine and 5- OHT compared to controls. In conclusion, the presence of physiological changes along with the significant neurobiological changes in the brain strongly support the efficacy of UCMS as a model of depression in the human being.