The study, carried out by the Joseph Rowntree Foundation, suggests that young carers tend to be tired at school and often miss days.

BBC: Play festival for child carers

Ofri, an assistant professor of medicine at New York University Medical School, says when patients complain about being tired, for example, she'll sometimes suggest they take a multivitamin, even though there's no proof they work against fatigue.

CNN: Is your doctor prescribing a placebo?