Mental health is defined by WHO as a state of well-being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community. It is related to the promotion of overall health, the prevention of disease, and the treatment and rehabilitation of people negatively affected by illness.

Depression is a common mental disorder that causes people to experience depressed mood, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, low energy, and poor concentration.

Depression is different from feeling down or sad. Unhappiness is something which everyone feels at one time or another, usually due to a particular cause. A person experiencing depression will experience intense emotions of anxiety, hopelessness, negativity and helplessness, and the feelings stay with them instead of going away.

Depression can happen to anyone. Many successful and famous people who seem to have everything going for them battle with this problem. Depression also affects people of every age.

Let Dr SEA explain it better in pidgin English.
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