Forget sex, drugs and rock'n'roll. Health, happiness and money are where students go off the rails.
After parents drop off their teenager and assorted electronics at the hall of residence for the first time, they will spend the long drive home - and possibly the months after that - worrying themselves silly about its welfare. Sex, drugs, and rock 'n' roll are the traditional concerns. And all the indications are there will be plenty of all those in the three or four years ahead. But if parents are to worry at all, these are probably the wrong things to be worrying about.

Young people away from home for the first time are going to take risks. One of my most bizarre aberrations after arriving at university after a pretty protected childhood was to hitch a lift on a lorry: the driver had the decency only to ask for a kiss when he dropped me off. I also acquired a boyfriend with a motor-bike to which I clung terror-struck for a few scary weeks, until I decided he was not worth the hassle. My mother would have torn her hair out.

Finding out how far you can go is part of growing up, and what's special about university is not that young people are experimenting, but that so many of them are doing it in the same place at the same time - and learning to survive. Most of us look back on our student days fondly and know that very few people came to serious harm.

These days most freshers will have sorted out their attitude to sex, drugs and alcohol long before they get anywhere near university anyway. As one colleague with a son at a sixth-form college said to me, they do what we did but they tend to do it two years earlier, between 16 and 18. What will be different for new students away from home is that parents are no longer close enough to provide a back-stop if they do get into trouble with drink, drugs or sexual relationships. And there are new problems which neither they nor their parents may have anticipated. It is those which on the whole lead to serious trouble.

As the Mori poll for the Adam Smith Institute, published last week showed, students these days take their studies and their career choices very seriously, but they also want to have a good time. At the hedonists' capital, Manchester, only one student in three said they had never used an illegal drug, and the average spend on alcohol was pounds 25.39 a week. Manchester students also seem to be having a fascinating sex life, with 10 per cent of them claiming to have sex every day and 40 per cent at least once a week.

If you need a large pinch of salt with all this - I know students who have invented whole new lives for unwary pollsters - it may not be so hard to believe that, generally, as Mori concludes, students spend more on booze than they do on books, and expect to have a seriously good time at university. Didn't their parents' generation?

Most parents learn to accept that late nights will as likely be spent at parties as on finishing an essay. But there are other aspects of university life about which they could usefully share their concerns with young people away from home for the first time in an environment in which they are expected to take a great deal of responsibility for their own work and leisure time.

One of the biggest risks for a student is actually not completing the course. Figures due out later this year are expected to show that one in four of the hopeful undergraduates who register each year will not graduate. This is a high figure, although not as high as in many other European countries, which work on the principle of cramming undergraduates in and booting them out again after a year. But failure at this level can be devastating for the individual involved, and sensible parents will be on the look-out for signs of worry about academic work - too many resits, depression and talk of changing course are clues.

One of the most common reasons for dropping out is that when students begin their course they decide they're studying the wrong subject. Part of the blame for this must lie with the scramble for places at this time each year as students turned down by their first choice university because their grades are not good enough grab any offer that some other institution makes. If you want to study history at Nottingham, it does not automatically follow that you'll flourish on a course in retail management elsewhere. Institutions sensitive to this problem make changing course easy. There is also a system for crediting students with undergraduate work at one institution so they can move to a course at another. Parents should be aware of the risk that unhappy students can fall by the wayside, never to return to higher education.

The other reason students drop out is financial. It is too early to tell whether the abolition of the maintenance grant will have an effect on drop-out rates, but it is already clear that many students are up to their neck in debt right through their courses, and a significant proportion are taking part-time work to help make ends meet. Even before the introduction of fees many parents have found that they had to subsidise students on the full grant and/or loan. That situation is hardly likely to improve and conscientious parents may find themselves under financial pressure as they make an effort to ensure their children are living in accommodation where snails do not march through the living room, and that they are living on a diet of more than just pasta.

Health is another issue about which parents might legitimately worry as their children take off into the murky world of student houses. Making sure that prospective students have a meningitis vaccination before they leave home is now Government-backed common sense. The student age-group is particularly vulnerable, and Southampton University, which lost three students to the disease in 1997, is leading the drive to make sure that all its students are immunised.

Suicide is another killer of young people, and depression very often afflicts those who are most conscientious about their academic work and most driven to succeed. The least parents can do is make sure that their children register with the excellent student health services that the universities run, and that they are also aware of the counselling services equally commonly available to support students with academic, financial or emotional problems - the sort of thing which can easily spiral out of control.

Parents can't take responsibility for what their already adult children do, but there may come a time when their help is needed. If you do nothing else, watch out for that moment. It might be crucial.