After listening to a radio interview I am convinced that I have had narcolepsy since childhood. It gave me a crippling complex, added to which I couldn't play sport, knit or sew or do maths or make relationships easily. Medical books suggested an underactive thyroid, though I didn't have all the symptoms. I now realise this wasn't the correct diagnosis. I am retired and realise it is too late to do anything about it, but would like to think this condition could not now go unrecognised for almost a lifetime.

Dr Fred Kavalier answers your health question:

Narcolepsy causes a sudden and sometimes irresistible urge to fall asleep. People with narcolepsy also sometimes get cataplexy, which causes sudden loss of muscle tone and collapse. A chemical in the brain – orexin – is deficient in people with narcolepsy. There are some drug treatments to help narcoleptics stay awake, but none of them completely solves the problem. The condition is undoubtedly under-diagnosed, and some people who are excessively tired during the day may in fact be suffering from a mild form of narcolepsy. There is a UK support group – the Narcolepsy Association UK – with a website that contains lots of good information and advice:

Please send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182 or email to Dr Kavalier regrets that he is unable to respond personally to questions.