For many patients at the Sanjali rehabilitation center in New Delhi, why they are there or how they lived before chronic mental illness took over their lives cannot be understood.

They are among the lucky few in India to receive regular treatment in a country where mental illness carries a huge stigma and psychiatric hospitals can be severe and frightening institutions.

Experts estimate around 20 million Indians suffer serious mental disorders, with most hidden from public view by their families.

For many Indians, their first instinct when symptoms of mental illness begin to manifest themselves in their relatives is to seek a spiritual explanation for the sudden change in behavior.

Families in denial will often take their loved ones to temples or faith healers, both of which abound across the country.

India does have some half-way houses that serve as temporary shelters for destitute and homeless mentally ill people, but there are few long-term options for families who are unable to look after their kin.

Nimesh Desai, head of psychiatry at the New Delhi-based Institute of Human Behavior and Allied Sciences, estimates India has fewer than 4,000 psychiatrists, and even fewer general mental health professionals.

"The lack of psychiatrists is bad and the shortage of psychologists, social workers and counselors is even more alarming," said Desai. "It meets about five to seven percent of the projected need."

One reason is a reluctance among young medical students to pursue a career in mental health. While India prides itself on churning out thousands of world-class doctors and surgeons, there is no prestige in psychiatry.