The Health Development Agency (Canning et al., 2004) concluded:
 

• Many studies have demonstrated that drug taking is strongly associated with early drinking, smoking and sexual activity. This suggests that drug use is one of the ‘risk-taking’ behaviours in young people.
• There are a number of dimensions for the concept of risk. Taking risk can be attractive for some people. Certain levels of risk can be accepted or rationalised on various grounds (for example, there is no such thing as risk-free living, or long-term risks might be irrelevant as drug-taking is only a temporary phase). This idea of rationalisation is one way perhaps of explaining how young people can go through a temporary period of drug experimentation.
• Although the distinctions between recreational drug use and problematic drug use are regarded as essential for the development of effective targeting in this area, there are those who question the use of both terms. Some prefer to think of a continuum of drug use behaviour, which involves pathways, careers and journeys rather than moving from soft or recreational drug use to hard drugs. 
• The majority of people who experiment or use substances do not become problem users. The likelihood of a young person becoming at risk has been associated with a number of risk factors (Table 1), although these links can be tenuous.
  

Table 1 Potential risk factors for drug use(adapted from Canning et al. 2004)

Reference

Canning, U., Milward, L., Raj, T., Warm, D. (2004) Drug use prevention among young people: a review of reviews: Evidence Briefing. The Health Development Agency.