There is a view among some parents in Scotland that it is better for teenagers to sit around smoking cannabis than go rampaging through the streets drunk.

But with new stronger forms of the drug fuelling concerns it causes severe mental illness and agencies backing pressure from Prime Minister Gordon Brown to toughen its classification, there is growing evidence and opinion that smoking joints is not a "safe" option.

Today a new report showed one in 10 Scottish 15-year-olds admit to regularly taking the drug - despite health risks and the threat of prosecution.

One parent whose opinions have been altered by differences she sees is Edinburgh mother Tina Woolnough, who has three children aged 14, 12 and nine.

Mrs Woolnough, chairman of family campaign group Parents in Partnership, said: "I know a number of young people who have been diagnosed with schizophrenia as a result of smoking cannabis. The evidence is these new heavily chemicalised forms are a serious mental health risk.

"I think there is real complacency among parents and young people about the dangers and police have responded to that view by not enforcing penalties."

At the Scottish Crime and Drug Enforcement Agency national drugs co-ordinator Detective Superintendent Willie McCall said police took a successful tough stance against cannabis which had not altered when the drug was downgraded to its current class C categorisation in 2004.

Highlighting a 10% rise in seizures of cannabis from 17,485 in 2003-04 to 19,215 in 2005-06, he also stressed that most young people do not take cannabis.

But he agreed that enforcement and education were needed. He said: "We have good evidence that enforcement is working but we also need to support drug education, which we are doing."

One such programme, supported by the Scottish Government, is Choices for Life and includes pop concert-style events to get across the anti-drugs message.

One drug worker, however, branded the scheme a "waste of time", saying there was "no evidence" educating young people reduced drugtaking. Instead, the worker, who chose not to be named, stressed projects should focus on arming children with accurate knowledge so they could make informed decisions.

The Scottish Drugs Forum, meanwhile, repeated warnings that, unable to afford high-strength skunk, teenagers were more likely to take cheaper, more impure forms of cannabis which could be contaminated with toxic chemicals.

David Liddell, forum director, said: "More research is needed to identify the health effects of taking large amounts of these types of cannabis. They also need more support - adult drugs services are not the place for young people to go."

In schools, teachers are well aware cannabis use by schoolchildren is a problem.

Jim Docherty, depute general secretary of the Scottish Secondary Teachers Association, said: "There are individual problems for teachers where young people clearly under the influence of these drugs come into school. Teachers have been trained to offer support but what is offered is not as good as it could be, and that is a matter of money."

Downgrading to Class C sent out wrong message'

Cannabis tends to be the drug of choice for people deciding to experiment with illegal substances.

Usually smoked, it increases the heart rate and has been linked to a range of health problems including panic attacks, paranoia and even infertility.

There are growing concerns that the drug, particularly a stronger form known as skunk, can cause serious psychotic illness including schizophrenia.

Those fears have spurred the UK Government to reconsider the classification of the drug.

In 2004 it was changed from a Class B to a Class C, reducing the penalties for possession and supply in a move which opponents said sent the wrong message that cannabis was not harmful.

Now Prime Minister Gordon Brown is pushing for it to be returned to the Class B category, bringing back tougher penalties to highlight the risks.

Under the current classification the maximum penalty for supply, dealing, production and trafficking is 14 years imprisonment.

The maximum penalty for possession of the drug is two years imprisonment.

Life for teenagers

Family life: Among 15-year-olds, 70% of boys and 74% of girls said it was easy to talk to their mother. This compares to 56% of boys and 38% of girls who said it was easy to talk to their father.

School: One-quarter of young people liked school a lot, girls more than boys. At 15, 34% of boys and 45% of girls said they felt stressed by schoolwork.

Food: The proportion of young people eating vegetables daily has increased slightly to 38% and those eating fruit daily has risen to 40%. One-third eat sweets every day, compared to 40% of girls and boys in 2002.

Physical activity: Just 29% of boys and 16% of girls met Scottish Government exercise guidelines. The amount of time spent playing computer games decreased with age. Among 11-year-old boys, 58% spent two or more hours computer-gaming on a school day.

Dieting: One in five boys has been on a diet, a 50% increase since 1990.

Wellbeing: Most young people, 84%, are satisfied with their life. Levels of confidence has grown among girls since 1994.

Substance use: More than one-quarter of young people have tried smoking tobacco and at 15 girls are more likely to have smoked than boys.

In 1990 14% of 15-year-old girls said they smoked daily. The total has now reached 19%.

Sexual health: Nearly one-third of 15-year-olds have had sex - 30% of boys and 34% of girls. In 2002 nearly one-quarter reported using neither the pill or condoms. This has dropped to 14%.

Bullying: Approximately one in 10 young people reported being bullied at least two or three times at school during the previous two months.