11 May 2013
An estimated seven million people in the UK currently provide unpaid care to a sick or disabled child or an adult who could not otherwise live independently.
Many of them are already known to GPs, but the Royal College of General Practitioners says that carers should be routinely screened by their doctors for signs of depression.
A number of carers have told the BBC News website about their experiences.
Philip Wright, Cumbria
"I have four sons. My 17-year-old, Aaron, is severely disabled with quadriplegic cerebral palsy. My wife Michelle, who shared responsibility with me, nearly died in 2011 with a brain aneurysm and a heart valve replacement. It has affected her left side and she is unable to look after our son Aaron any more. So my 19-year-old helps to look after her.
"Aaron needs 24-hour care. I am up most nights and I get no sleep whatsoever. My 19-year-old son looks after Aaron on Wednesday nights so I can get at least one night's sleep a week.
"School holidays can be hell. Aaron doesn't like too much sun so we tend to stay indoors a lot. I'd like to take my boys out for the day but it's just not possible and I can't expect my eldest son to look after everyone else.
"Please don't get me wrong, I get a lot of happiness from my family so don't think it's all bad, but there are some very, very hard times.
"I love my family to bits and would do all I can but when you get no time to yourself and never get chance to socialise anymore it has become very stressful and lonely.
"I think these tests would make me feel that my welfare is being looked after which I would like. But what would really help is someone coming to the house to help me and to give me a break."