Excessive intake in those who already suffer from anxiety or depression can result in more anxiety, fatigue and depression as the effects wear off. The effects of caffeine include an abrupt increase in cortisol, a stress-related hormone that gradually builds up throughout the morning to help us perform daily tasks. But coffee keeps cortisol and adrenaline at high levels, especially when it's drunk throughout the day, and it can disrupt sleep cycles. In the morning, the body is already working with a hydration deficit, and coffee is a mild diuretic that can exacerbate dehydration. Want to keep those whites pearly? Cut back on coffee, which can stain teeth. The bottom line is that coffee is OK in moderation and infrequently - limit yourself to one or two cups in the morning.