A primary care physician or a mental health professional usually can diagnose depression by asking questions about medical history and symptoms. By definition, major depression is diagnosed when a person has many of the symptoms listed above for at least two weeks.
Many people with depression do not seek evaluation or treatment because of society's attitudes about depression. The person may feel the depression is his or her fault or may worry about what others will think. Also, the depression itself may distort a person's ability to recognize the problem. Therefore family members or friends may need to encourage the depression suffer to seek help.
There are no specific tests for depression. However, it is important to be evaluated by a primary care physician to make sure the problems are not being caused by a medical condition or medication.