Effect of long-term caffeine administration on depressive-like behavior in rats exposed to chronic unpredictable stress.

Chronic unpredictable stress (CUS) was used to study the effects of a long-term treatment with either caffeine (8 mg/kg, orally) or desipramine (DMI) (10 mg/kg, intraperitoneally) in Wistar rats. The CUS procedure was applied for 6 weeks. Animals underwent a 2-week drug-free CUS procedure.