By Michelle Roberts
BBC News health reporter
Naughtiness can be fun
More and more badly behaved children are being diagnosed with conditions like ADHD.
Latest figures show global use of ADHD drugs has nearly tripled since 1993.
In England and Wales alone, prescriptions for the standard treatment, a drug called Ritalin, rocketed from just 4,000 in 1994 to 359,000 in 2004.
At least one in 20 schoolchildren - 360,000 in total - is thought to have some degree of attention deficit hyperactivity disorder (ADHD).
Some experts say this is the tip of the iceberg and there are many more children out there going undiagnosed.
But what ever happened to sheer naughtiness?
Critics argue bad behaviour in children is being over-medicalised, and even that the labels are being used to excuse unruly behaviour.
Indeed, the US psychiatrist who identified attention deficit disorder says up to 30% of youngsters classified as suffering from disruptive and hyperactive conditions could have been misdiagnosed.
Dr Robert Spitzer, professor of psychiatry at Columbia University in New York, says many may not really be ill and may simply be showing perfectly normal signs of being happy or sad.
Dr Sami Timimi, a consultant child and adolescent psychiatrist in Lincolnshire, says there is a real danger that the diagnosis is becoming a dumping ground for simple bad behaviour.
"There is no test for ADHD. It is diagnosed on the basis of a questionnaire, which is subjective.
"We are creating ADHD out of behaviours that would previously have been perceived as normal.
"There is a temptation to use it as a get out - by doctors as well."
He suggested undesirable behaviour might be more common because family life had changed.
"We have had the demise of the extended family, increasing separation and divorce and more working parents.
"It is harder than ever to be a normal parent these days. The expectations are higher."
Disobedient or disorder
But he said parents should not be held solely to blame - many other factors could also be involved.
Children are living more sedentary lifestyles, sitting in front of TVs and computers for much of the day, and are eating more additive-laden foods.
He said education systems had also become more target-driven.
He pointed out that the pharmaceutical industry had profited from rising cases of ADHD, by selling more stimulant drugs.
Vivienne Streeter, director of family services for the British Institute for Brain Injured Children, says disorders such as ADHD can be distinguished easily from simple naughtiness.
"ADHD is a definite medical condition. It's there from birth, is lifelong and present in all situations. You can't get a child who is just ADHD at school or at home.
"Compare that with a naughty child - they can be very good in one setting but chose to be naughty or push the boundaries in another. That's when poor parenting, housing and diet come into play."
But she conceded that it could be hard for an outsider merely observing bad behaviour to separate the two.
Indeed, there have been cases where children diagnosed with conditions like ADHD have been hauled before the courts and given anti-social behaviour orders (ASBOs).
On the flip-side, medical diagnoses are also abused.
Ms Streeter explained: "There are certainly some people who will use it as an excuse.
"A lot of parents will say their child is hyperactive or has ADHD. I have even had medical people who have said a child is ADHD and they are not."
But Dr David Coghill, senior lecturer in child and adolescent psychiatry at Dundee University, says in the UK the main problem is under-recognition of behavioural disorders.
Difficulty remaining seated when required
Difficulty awaiting turn in group situations
Difficulty following instructions
Difficulty in playing quietly
Often shift from one incomplete activity to another
Often interrupts others
Often engages in physically dangerous activities without considering the consequences
Andrea Bilbow, chief executive of ADDISS, the national attention deficit disorder information and support service, agrees.
"We are only just touching the tip of the iceberg. Not even one in every hundred children with ADHD is being picked up.
"Parents do not take their child to see psychiatrists or paediatricians unless they have a problem.
"Why would you want to use a label for a child who does not have a problem?"