If you think a drug you're taking might be causing your depression, you may be right. Certain medications prescribed for various medical conditions do cause such feelings as sadness, despair, and discouragement. And those are feelings that are often associated with depression. Other medicines prescribed for medical problems can trigger mania (excessive elation and energy) that's usually associated with bipolar disorder.

Medications that cause mania or depression appear to alter brain chemicals in some way. And even though the drugs may be necessary to treat the condition, the side effect is hardly acceptable. As an example, isotretinoin (Absorica, Amnesteem, Claravis, Myorisan, Zenatane), which is prescribed for the treatment of acne, has been found to also sometimes cause depression. So have oral contraceptives, high blood pressure drugs, and even statins that treat high cholesterol.