Hands up all those who have had a sneaky fag behind the fence, or smuggled booze into the school disco. We've all got well-worn tales of misspent youth. But how do you reconcile that with the recent disturbing story of an 11-year-old Glaswegian girl who collapsed in class, the result of two months of "chasing the dragon" (smoking heroin)? Or you discover that one of your pupils is pushing drugs? Scottish police figures show more than 70 children were arrested last year for dealing, including heroin.
What do you do if, as in one teacher's experience, a 13-year-old turns up for morning registration "steaming drunk". Our pubs can stay open all day and recreational drug use is linked with glamour and celebrity. What message should teachers give to young people in school? Are there times when teachers should intervene in the antics of adolescent children, or is it not a school concern?
The country currently appears to be in a panic about teenage misdemeanors; recently we learned that teenage girls in Britain are among Europe's worst binge-drinkers, according to the Schools Health Education Unit (SHEU), and cannabis use by schoolchildren has increased tenfold since 1987.
But is under-age drinking something new? Gary Scrafton, a senior teacher from the north east, thinks not: "Teachers cut themselves off from their own experiences. I remember drinking in the local pub as a teenager but, with adults present, there were very clear expectations on our behaviour.
Now teenagers head for the park. With no adult around, it often ends in violence."
An SHEU study of 2004 also highlighted this preference for drinking outside, or at friends' houses, usually without parental consent or knowledge.
While there is a growing awareness of drugs and their dangers among teenagers, the exception is cannabis, according to David Regis at SHEU.
"Year 10 students don't see it as unsafe." It is cheap and easily available and many teenagers see it as an alternative to drink. Although it has been reclassified as a class C drug for adults, teenagers are often unaware that it is still illegal and that they can end up with a conviction.
Cannabis is often seen as preferable to cigarettes. Possibly the anti-smoking lobby has had an impact; with most 10 to 11-year-olds adamantly anti-smoking and 35 per cent of 15-year-old girls still not having tried cigarettes, according to SHEU.
Identity plays a big part in the sub-cultures that develop within schools.
The illegality of drug-taking fits in with the age-old teenage concepts of "us against them". It's not shady dealers but, according to teenagers I spoke to, it's other students who make a bit of cash by dealing, even on school premises. If it doesn't happen at school, a friend or an older sibling will know a supplier.
Unless you're an expert or it's an extreme case, it can be hard to gauge whether a pupil has taken drugs. You can't smell anything, the effects wear off quite quickly and signs of usage mirror much of what is seen as "normal" teenage behaviour.
Where do you stand legally? In any confrontation with a student, always have a witness and record the incident. You must have the student's consent to carry out a personal search, although possessions can be checked. What happens thereafter will depend on your school's policy.
Although experts advise against excluding pupils from school for smoking and alcohol incidents, a study of 1,000 schools by Manchester Metropolitan University showed 1,400 temporary and 400 permanent exclusions.
Police, social services and education authorities have developed various initiatives to tackle drug abuse and provide valid drugs education in schools, the latest including the national FRANK campaign and the Blueprint scheme in the Midlands and north of England.
Sarah Blackshaw, Lewisham's drugs adviser, says schools' reactions to drugs education and dealing with individual problems are varied: "Some schools brush the problem aside, although there are more schools now taking up the training and support offered."
Mary Jo Hill, an adviser with the Healthy Schools Partnership, adds: "In the last year there has been a greater commitment from primary schools to address drugs education. Local Healthy Schools programmes support them with schemes of work and curriculum materials, also providing drug awareness sessions for parents.
"In secondary schools, where there is a more complex set of problems related to smoking, alcohol, and cannabis in particular, there is a need to address individual students issues, particularly those most at risk of drug abuse. However, you don't want to draw attention to a school that could be labelled by a local community as one with a drugs problem. It's a difficult balance to achieve given the negative effects of the media and public perception."
If you're a form teacher you may have to provide drugs education, usually as part of the PSHE curriculum. Students and teachers alike often feel what's offered is too dry and pupils' awareness goes beyond what is taught.
Budget constraints can also see PSHE losing out to more academic subjects.
Find out what scheme of work your school uses and what local support is available. Hamsey Green junior school in Warlingham, Surrey, uses a scheme of work in Year 5 provided by the local authority, with input from a police officer whose daughter had a bad drugs experience.
Milica Reardon, a key stage 2 teacher at the school, feels it's this personal insight which hooks the pupils. "They're often anxious about envisaged pressures when they go to secondary school. They can relate to what PC Campbell says about drugs misuse, both in the language he uses and in identifying with a real situation. He's very thorough in offering strategies to help them cope."
What goes on at home also affects attitudes. Parents may have an ambivalent outlook on drinking and drug-taking. At secondary school it's rare to have regular contact with parents, but I can remember the aroma of alcohol emanating from certain parents when I was a primary teacher.
While it's your right to refuse a parent access if you're concerned for the child's safety, it's a hard one to call. Building a sense of trust with the child and giving them the space to approach you could prove a lot less distressing. You can't promise confidentiality if a child discloses to you, but if you're aware of possible problems at home you may be able to advise on possible solutions or sources of help.
"Dealing goes on in school. Kids go to the toilet to smoke. Even fitting smoke alarms might lessen the problem. Years 7 and 8 girls are getting drunk at parties. They start off being anti-drugs, but as they get older their attitudes change. By sixth form more kids take drugs."
Esther, 16, London comprehensive
''We don't learn anything new. A film about someone who's had a bad experience would have more effect."
Aysha, 13, East Sussex comprehensive
"They shouldn't tell you about drugs - you might want to try them then. I liked it when they showed us the effects of smoking on your lungs in an experiment."
Chloe, 13, East Sussex comprehensive
"Our school's really image conscious. They'd be afraid of admitting any drugs connection."
Joe, 15, suburban city academy
"I saw a boy teaching a girl how to roll a joint in class. Maybe the teacher didn't notice or she just decided to ignore it."