Depression manifests itself in different forms. Some feel sad, others become agitated and aggressive. While some lose their appetite, others binge eat. Some may have disturbed sleep and others may find it hard to stay awake. Social withdrawal, diminished sex drive, suicidal tendencies and lack of concentration are some other tell-tale symptoms of depression.

"No two patients have identical symptoms," says Dr. Vihang Wahia, a practising psychiatrist in Mumbai.

Of course, all human beings have variations in their moods. Scientists describe mood as an amalgam of emotions such as anxiety, anger, pride, love, pain or joy that a person feels over a period of time.

The emotions of feeling sad, unhappy or disappointed are part of a human being's normal existence. Such emotions are often associated with failure in academics, break-up of a relationship, setbacks in a financial investment or the death of a loved one. However, depression as a disease sets in when a person fails to bounce back from a personal setback like this.

"Diagnosing depression early is very important," says Dr. Wahia. In most mild cases of depression, patients can be brought back to normality just by good counselling. "Clearing some cobwebs of life is all that required," he observes. But it's different in the case of those who suffer from moderate to severe depression. Certain changes occur in their brains and, in addition to counseling, they require medication to help re-wire the brain.

It is estimated that 5~10 percent of the Indian population suffers from depression at any given time. And women seem to be more prone to the disease than men. The risk of developing depression is 10~20 percent in women and slightly less in men. What's more, the male to female ratio for developing depression is between 1:2 and 1:3, says Dr. Dhanesh K. Gupta, associate professor. This is because women undergo frequent hormonal changes in the reproductively active years of their life.

In India one of the major problems in treating the growing incidence of depression is the fact that it is often not diagnosed at all. Either the doctor fails to see its severity in a patient or patients simply don't come out and report their condition. Of course, more patients come forward with the problem now than earlier, when it used to be viewed as a social stigma. But even so, many cases are not reported early enough. As Dr. Rajesh Sagar, associate professor of psychiatry, says, "Depression is grossly under-diagnosed and undertreated in India."