Not because they can't have a Playstation 3, sleep over at their mate's house or any other of the day-to-day annoyances of modern childhood.

They will be withdrawn, unable to sleep, feeling useless, worthless, unloved. Some will feel suicidal.

They will be clinically depressed.

That's the shocking state of the city's mental health according to experts who treat sufferers and help them cope with the crippling negativity they feel about themselves and their lives.

It's often difficult for parents to spot the signs – especially those brought up in an era when 'fed-up' kids were treated to an ice-cream or a clip round the ear to snap them out of their sulk. But medics now recognise children as young as five can be affected.

Dr Rick Hughes is a Consultant Adolescent and Childhood Psychiatrist for Sheffield's Children's NHS Trust.

"When you talk about depression in adolescents and children you are talking about something more than briefly being miserable or sad because of a setback," said Dr Hughes one of eight NHS Trust Adolescent and Childhood Psychiatrists in Sheffield.

'The message though is that depression in young people is rare'

Dr Rick Hughes

"We are talking about severe symptoms for several weeks having a serious impact on their well-being and ability to function. The message though is that depression in young people is rare. Among primary school age children it's less than one per cent.

"It is more common after puberty, three to four per cent of teenagers might suffer from depression.

"In Sheffield one per cent of children is 1,000 people but they will probably be teenagers rather than young children."

It may be related to the changes in young people's bodies in the teenage years, physiological changes to hormones and the brain.