Thomas and colleagues (2008) undertook a substantive review of the evidence on effective early interventions for at-risk youth, which included a review of existing systematic reviews and meta-analysis; the authors identified the key categories of risk factors relating to poor outcomes for at-risk youth. From this review of the literature, they concluded that family, school, individual and peer, and community were the key risk factor categories. They investigated other risk factors for poor outcomes, including teenage pregnancy, youth homelessness, mental health, youth offending and alcohol and drug use, but did not include these factors in their final analysis. The NACD study used similar categories to group 70 potential risk factors for substance use into five broad domains: individual, peer, family, school and community. The NACD authors developed an approach and questionnaire based on their reading of individual academic studies. 

 

Frischer and colleagues (2007) undertook a systematic review of the literature when investigating predictive factors for illicit drug use among young people and presented an alternative typology. They grouped the findings of 62 high-quality quantitative studies into four domains: personal (biological and psychological), personal (behavioural and attitudinal), interpersonal relationships, and structural (environmental and economic). These domains differ from those used by the NACD and by Thomas and colleagues. When Frischer and colleagues completed the synthesis, they were able to explore the nature of the behavioural and attitudinal domain, which is perhaps the most amenable to change and receptive to interventions to prevent alcohol and other drug use; the more we know about why and how young people make decisions about substance use, the better interventions can be tailored to intervene in this decision-making process.

 

Frischer and colleagues reported that ‘the available evidence indicates that higher levels of drug use are strongly associated with young people’s reasons for using drugs after controlling for risk factors’ and they noted that ‘qualitative research shows that the context in which young people experience drugs is crucial for understanding how risk and protective factors operate in relation to experimental and sustained drug use’.

The authors’ finding that ‘the key predictors of drug use are parental discipline, family cohesion and parental monitoring’ is echoed in the NACD study. However, they did not find, as the NACD study did, that the school environment strongly influenced the decision to use drugs. Frischer and colleagues found that ‘age is strongly associated with prevalence of drug use among young people’, while the NACD study found that age, after controlling for other factors, has a minor influence on the decision to use drugs.

 

Scaife and colleagues (2009) developed a theoretical framework to assist with the design of interventions based on the findings of Frischer and colleagues’ systematic review. Scaife and colleagues argued that the work of Frisher and colleagues shows that ‘[young people’s] beliefs explain just as much variance in drug [use] as risk factors do...[consequently]...we need to consider more explicitly the extent to which such beliefs are linked in with psychologically meaningful group membership, and then transmitted into group behaviours’. According to Scaife and colleagues, young people’s primary group membership derives from their peers; they are often part of one or a number of friendship-based groups. The sociological literature, drawing on the school of symbolic interactionism, refers to such groups as ‘reference groups’ and, according to Scaife and colleagues, these ‘reference groups’ are important sources of norms. The authors highlight a number of studies that show how young people’s motivations for engaging in risky drinking are linked to social group memberships, activities and cultures. One example is drinking to gain respect and image in the social group. The NACD study did not explore whether the substance-use behaviour reported by young people was influenced by the norms, real or perceived, that they associated with their peer group.  

 

While the NACD study identified risk and protective factors, it did not answer the question ‘Why do some young people decide to use drugs while others do not? Ajzen (1991, cited in Scaife et al. 2009) developed the ‘theory of planned behaviour’ and hypothesised that young people possess the capacity to perform a cost-benefit analysis of a situation, regardless of their family or school experience; their behaviour is intentional, it symbolises and affirms their group membership and it resonates with the norms of the peer group. This hypothesis by Ajzen could explain an important finding in the NACD study, ‘if friends use substances, the young person is at a considerably greater risk of using the same substances’. For example, if young people perceive substance use to be a norm among their peers, this perception, real or imagined, reduces its risk profile. In effect, young people may actually perceive substance use as a protective factor, as it may constitute an important symbolic ritual of connectedness with their peers and in some cases may protect and enhance group identity. Such considerations need to be built into prevention interventions that seek to tackle and reduce the risk factors associated with substance use.