Depression and Immunity: A Review

Depression is a very common phenomenon. Most of us have experienced some transitory period when we have felt sad and worried; during studying, sleeping and eating patterns have been disturbed. Depression is the foremost mental health problems round the globe. It is basically a disorder of mood or feeling. When depression is severe, persistent and disabling of everyday physical and social functioning, it is easily discernible. At other times, the distinction between normal fluctuation of mood and depression may not be very clear. Feelings of sadness, frustration and discouragement are part of the normal range of human emotions. However, these fluctuations tend to be short lived, do not become overwhelming in their experience, do not impair reality testing, do not profoundly alter self-esteem and do not generate suicidal thought or behaviour. In addition normal mood fluctuations do not produce persistent disturbances in sleep, appetite or motoric activity.