The dependence of the disabled, the sick and the mentally infirm on those who care for them outside institutional settings, constitutes a major constraint on the life-style of the carers, whose quality of life may be below that of the disabled. This is especially the case where the burden falls on relatives and friends who are seldom in a position to complain or to modify their situation, whether or not they would wish to do so.
In the UK in 1990 it was estimated that 6 million people look after some 700,000 sick, disabled and mentally infirm outside institutional settings requiring constant care and attention, often calling for more than 50 hours per week of time on the part of relatives and friends.