Ask a teacher at an international school in Hong Kong about the incidence of illicit smoking and drinking among teenagers and they'll probably say with boys, the issue is likely to be drinking, while with girls, it's smoking.
Boys drink because they think it's macho, and it seems acceptable because they see Dad downing beers and having a good time with his mates at his club or socially. That doesn't mean teenage girls don't drink, just that it's more likely to be boys with bottles in their bags.
Girls, generally speaking, prefer smoking for a number of dangerous reasons. Several supermodels do it, so it's perceived as fashionable. But more pernicious than that, the supermodels often claim it helps them control their weight.
Various theories abound about the effect of smoking on metabolism, fuelled by the reality that many smokers gain weight when they quit. Often this has more to do with them taking up snacking than anything else. On the one hand, nicotine acts partly as a stimulant so smokers often burn more nervous energy from fidgeting than non-smokers. Yet not all former smokers gain weight. Ex-smokers who have not mentally kicked the habit substitute one form of oral gratification for another and sugary snacks tend to be first choice. That's a huge calorie increase in the form of refined white sugar that the body readily converts to fat.
Former smokers may also feel unsatisfied and deprived, which makes them eat more - and drink more alcohol - than before, in their search for the elusive feeling they think they got from cigarettes.
But what teenage girls don't realise about supermodels and Hollywood actresses is they often have serious eating disorders and drug problems. These have far more to do with their emaciated appearance than any dubious metabolism-stimulating effects of tobacco. Supermodels use cigarettes or cigars as props. Instead of playing with lettuce leaves while everyone else eats, they light up. It gives them something to think about rather than gnawing hunger pangs. The damage caused by this lifestyle is not so obvious while they're working: the dull grey complexions and premature ageing caused by the nicotine are disguised by layers of foundation and clever lighting.