Mental handicap or learning disability is about those people in the lowest 3% of the IQ curve.

The incidence of severe Mental Handicap is 3 per 1,000 (IQ < 50) and may be the consequence of genetic abnormality, chromosome disorders or severe brain damage.

Moderate handicap (IQ 50-70) is more common among poor deprived populations; with effective parenting, education and care such people can learn to live and live well; without this they will decline into a quasi animal state with associated behavioral problems and frank mental illness.

People with learning disability often have other congenital problems-cardiac, orthopaedic, neurological, ophthalmic.

The cause of much mental handicap is unknown The setting up of registers of mentally handicapped people enables the effective provision of health, social and educational services determined by and tailored to their needs.