Q: My 24 years old sister has a habit of eating 0.5 fine leads (used in pencils), chalks, nails and skin. Her haemoglobin level is 6. Is her haemoglobin low because of eating lead? Further, why does she eat all these things and what problems can she face because of her eating disorder?

A:Your sister is suffering from pica, which is the persistent eating of non-nutritive substances at an age when this behaviour is inappropriate. It is commonly seen in children and when present in adults, may suggest a developmental disability. It can also be present in young pregnant women in their first pregnancy. The cause for this is unknown and a lot of theories abound that implicate cultural, socio-economic, psychodynamic and other factors. Some nutritional deficiencies (iron, vitamins, zinc, calcium etc.) may be associated with this habit. It is not clear whether iron deficiency leads to pica or vice-versa. Hunger or malnutrition may sometimes lead to it. Consultation with a psychologist or psychiatrist is necessary, as behavioural therapy has been seen to be effective in such cases.