The Press Association have approached councils across the UK and found children as young as four being referred by education and children's services to alcohol and drug specialists.
In the Freedom of Information request, more than half of under-13s - 59% - received treatment for cannabis misuse, while a third were treated for alcohol misuse.
A small number abused solvents.
Eight-year-olds had been referred to services in Waltham Forest and East Ayrshire, while nine-year-olds had been referred in Herefordshire, Liverpool, Oxfordshire, Rutland, the Scottish Borders and West Berkshire.
Authorities in Bury, Calderdale, Halton, Hull, Monmouthshire and Rochdale had seen 10-year-olds referred.
Some 366 children aged 12 or under were referred for treatment in 2012/13 in England, according to the most recent figures from Public Health England, compared with 433 in 2011/12.
Steve McCabe, shadow minister for children and families said he was "shocked" by findings stating children as young as four are being referred to drug treatment centres in the UK.
He said: "The government's current strategy towards drugs isn't working. This highlights the need for an urgent improvement in children and adolescent mental health services".
McCabe continued by saying a previous Home Affairs Select Committee set up "was interested in the way Portugal manages drug problems" and that there needs to be a "proper strategy to deal with many of the challenges of growing up."
The head of the influential House of Commons home affairs committee says he is "deeply concerned" at an investigation showing children as young as four are being treated for drug and alcohol misuse.
Labour MP Keith Vaz called on parents to do more to prevent risks to their children.
"It is right that these youngsters receive the appropriate help but we must look at the source of their problems," he said.
"It is vital that parents take responsibility and additional support is given to them in order to prevent children being exposed to drugs and alcohol in the first place."
It is "vital" to improve education programmes to stop young children having to be treated for drug and alcohol misuse, charities have said.
A survey by Mentor UK, who works to protect children from drug and alcohol misuse, suggested youngsters are not getting enough information.
The charity's director of programmes, Andrew Brown, said:
"We think it is vital that alcohol and drug education improve. Our own survey of teachers suggests that at the moment delivery is inconsistent, and that the norm is to timetable only one or two sessions a year.
Children as young as four years old are among hundreds of young people being sent to specialist drug and alcohol treatment centres.
An investigation by the Press Association found that councils across the UK were referring youngsters to the centres.
Experts said the most common reason children had access to drugs was through their parents.
As teachers announce plans that could result in strike action there seems to be little support for any walk outs with parents reacting angrily to the plans.
- Helen Nellie Chadwick: Surprise surprise think parents should unite as one to stop the fines for taking kids out as its prejudice as it doesn't apply to the disruption that strikes cause let alone the poor pupils about to do their exams.
- Gypsy Bluebell: Outrageous. Parents can't take children out of school because of disruption to the rest of the class... I have no sympathy with them, whatsoever.
- Ron Lock: Why don't they have their strikes in August, as a nurse I am getting fed up with this... Maybe we should refuse to treat teachers when they go on strike!
- Tracy Trotter: Find a different way than walking out. It not only hurts the gov it hurts every parent and costs [them] to find childcare.
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The Department for Education has hit out at the National Union of Teachers over proposed strike action in June, saying it will "damage the reputation of the profession".
A spokesperson added that it was up to headteachers to ensure their staff have manageable workloads.
Ministers have met frequently with the NUT and other unions and will continue to do so. Further strike action will only disrupt parents’ lives, hold back children’s education and damage the reputation of the profession.
It is important that teachers work closely with school leaders to ensure that their workload is manageable. We trust the professionalism of our headteachers to monitor their staff's workload and address any issues.
Teachers have taken to Twitter in support of the news that summer strike action has been approved by the National Union of Teachers (NUT).
#NUT2014 so pleased that we have passed the stand up for education motion. Loved the fact that everyone stood up and clapped at the end!
#NUT2014 Strike action isn't certain, it is an OPTION, to be taken if the Govt won't negotiate. The Govt can prevent it, if they want to.
The National Union of Teachers has voted for a series of fresh strikes, starting with a national walkout in June.
The action relates to a long-running dispute over pay, pensions and working conditions.
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