The survey found more teenage girls smoked than boys

More than 5,000 pupils from 30 schools, aged between 14 and 15, took part.

The survey by West Sussex Primary Care Trust (PCT) and the county council was to develop health strategies.

Dr Farhang Tahzib said there was "an urgent need" to work with young people and their families to ensure they made informed lifestyle decisions.

This is a crucial piece of work Dr Farhang Tahzib

The joint director of public health and well-being said the "valuable" piece of work provided "much-needed information".

The survey will be repeated in 2009 so that schools and young people's services can track the progress of initiatives.

He said: "This is a crucial piece of work as it provides schools with in-depth information on the lifestyles of their pupils, and provides a baseline from which they can plan improvements."

'Pupils bullied'

Findings included that 30% of girls were smokers compared with 20% of boys.

One in 10 pupils reported regularly drinking with the intention of getting drunk.

And one in 10 pupils was a current user of cannabis, while 3% were regular users.

The survey also showed that one in five pupils was consuming the recommended five-a-day portions of fruit and vegetables.

65% of boys took part in moderate physical activity four or more days a week and 35% of girls did the same.