Class A drugs

Class A drugs include opiates such as heroin, cocaine, ecstasy, hallucinogens and amphetamines (when injected). A reduction in the use Class A drugs and the frequent use of any illicit drugs among young people are one of the targets launched by the UK Drug Strategy (Drugs Strategy Directorate 1998).

Current drug use & factors associated with the use of drugs 

It has been identified that the sequence of drug use tends to follow a series of stages. The use of licit drug use often precedes cannabis use. While cannabis use usually occurs before the initiation of ‘harder’ drugs use such as heroin and cocaine (see Golub & Johnson 2002). According to this evidence, it can be expected that the recognition of future ‘hard’ drug users should correlate with identification of current cannabis users. However, there is accumulating evidence to suggest that the initiation of ‘hard’ drugs use does not always follow the ‘gateway’ sequence, particularly among sub-populations of young people. A quarter of a British clinical sample reported that they started to use cocaine and heroin before they began to use licit drugs (Sanju & Hamdy 2005). The gateway theory could not best characterise drug initiation sequences reported by an US population of arrestees (Golub & Johnson 2002).  

In contrast, there is some general population evidence to suggest that the gateway sequence most commonly characterises the ordering of drugs use in the USA (Golub & Johnson 2002; Morral et al. 2002). Also, the cannabis gateway effect has been adequately explained by a common factor, a propensity for drug use (Morral et al. 2002). The gateway sequence observed in this population could be a reflection of ordering of opportunities to come across particular types of drugs. Individuals in the population may have more opportunities to obtain or be offered cannabis than any other types of illicit drugs. There is some evidence to support this assumption. Data from a survey of secondary school students in London revealed that 46.3% of the respondents said they have been offered cannabis while 10% of them reported that they had been offered cocaine (Manning et al. 2001). Furthermore, the data have shown that the access to drugs does not necessary lead to the use of drugs. About a third (34%) of those who were offered cannabis reported that they did not take the drug. While the majority of those who were offered cocaine said they did not use the drug (70%).  

Manning et al. (2001) have suggested that the higher prevalence of cannabis use (compared to cocaine and heroin use) may also result from young people’s assumptions or perceptions about cannabis. These consist of low levels of perceived health risk, high perceived controllability and the short-term nature the effect with a limited impact on other activities. However, work with ecstasy users (Gamma et al., 2005) suggests that many are fully aware of the associated risks but discount them because of comparisons with other drugs/activities (relative risk), or because they hold no personal significance (affective risk assessment). Drug price (and perceived quality) may be another important factor (Manning et al. 2001; Sumnall et al., 2004). One of the simplest applications of this type of economic analysis is the study of constraints on access, in particular the purchase price of controlled drugs. Cannabis is cheaper than heroin or cocaine and young person’s budget is limited. The drop in price in ecstasy to £2 or £3 in some regions therefore needs to be monitored (Sumnall et al., 2004). UK school survey data on drug use has shown that a minority of 14 – 15 year olds (up to 14%) said they receive more than £30 per week from pocket money and jobs (Schools Health Education Unit 2005). The results of a survey of licit and illicit drug use among Scottish school children have also revealed their limited budget for drug use (The Child and Adolescent Health Research Unit 2004). The average amount spent on drugs was £11 per week among the majority of those who reported monthly use of drugs (65%). In this context, decision making may be constrained by the economics of controlled drugs. According to the matching law (Herrnstein, 1970), increasing/decreasing the benefit or decreasing/increasing the cost of a particular activity will alter its value relative to all available alternatives, which will then alter the allocation of behaviour to that activity. That is, the proportion of behaviour allocated to any particular activity will match the relative reinforcement gained from it (Heather and Vuchinich, 2003). Therefore, the individual will allocate their limited resources, such as time and money, to maximise their utility (i.e. a favourable cost/benefit ratio) from the options available to them. In relation to drug use, it is hypothesised that the value of drug use is a function of the cost/benefit ratio of consumption relative to the cost/benefit ratio of all other available alternative activities.  

There is evidence to suggest that the decision to take a particular drug can be influenced by numerous factors including physical psychological states, commitments, boundaries, environment, availability, finance, friends, peers and the media (Boys et al. 1999). However, one of the most important factors appears to be individuals’ specific expectancies about the functions of the drug (Boys et al., 2001; 2003).   

It should be noted that the initial experiences of a drug does not necessary lead to regular use but the magnitude of a positive experience with the initial use of cocaine has a marked effect on the escalation, or problematic use (Davidson et al. 1993). The likelihood of developing regular use of a particular drug as a result of having ever used was variable between different types of drugs (Manning et al. 2001). It was reported to be higher for cannabis (33.9%) than for amphetamines (12.8%) and cocaine (13.4%) in a sample of school students in London (Manning et al. 2001).  

As can be seen from the evidence, the decision to initiate the use of a particular drug can be one of behavioural choice, which is largely determined by a complex interaction of psychological, environmental and biological factors. Because the use of drugs is often associated with immediate rather than delayed benefits (an immediate short-term ‘buzz’) and later costs (psychological, physical, social and financial damage), the decision may also reflect impulsive decision-making (Kirby & Petry 2004). Some authors have conceptualised problematic drug use as a failure in the control of impulsive behaviour. 

Vulnerable groups

Several groups of young people have been identified as having higher risk of developing problematic drug use (Canning et al. 2004). These groups are often termed ‘vulnerable’ groups and include homeless young people, school excludes/truants, young offenders, cared for children, young people who work in sex industries and children of drug using parents.

These subpopulations of young people are reported to have high levels of drug use compared to the general population. The data from the 2003 Crime and Justice Survey (Becker & Roe 2005) have revealed that 16% of the vulnerable young people reported to have used Class A drugs in the previous year. The reported use of Class A drugs in the past 12 months was markedly low among young people in the general population (4%). Among the identified groups, truants had the highest levels of drug use (16%) while those in care had the lowest levels of use (5%). There may be particularly vulnerable sub-sets of young people within these classifications. Members of more than one group reported higher levels of Class A drug use than members of just one group (more than one 39.0%; one group 18.0%). These findings indicate that it may be possible to provide targeted Class A drug prevention to young people who belong to these groups. However, it must be noted that a large proportion of young people who are part of these groups do not take or develop regular use of Class A drugs.  

Risk factors

Successful targeted drug prevention programmes require the accurate and reliable identification of subgroups of young people who have higher risk at developing drug use than the general population. A number of biological, psychological and situational factors that can predict drug use have been identified. Inherited vulnerability (for males), maternal smoking and alcohol use, extreme social disadvantage, family breakdown, and child abuse and neglect are the earliest risk factors that can increase the probability that infants develop behavioural and adjustment. When children enter school, risk factors include experience at school (school failure) as well as intra-individual factors (childhood conduct disorder, aggression) and familial experiences (favourable parental attitudes to drug use). From adolescence, types of risk factors widen and include low involvement in activities with adults, the perceived and actual level of community drug use, availability of drugs, parent-adolescent conflict, parental alcohol and drug problems, poor family management, school failure, deviant peer associations, delinquency and favourable attitudes to drugs (National Drug Research Institute and the Centre for Adolescent Health in Australia 2004). Some researchers have identified risk factors for the onset of cocaine use. Relatively young age, less family caring, less coping ability, infrequent church attendance and low educational aspirations were significantly associated with cocaine use among students attending dropout prevention/recovery high schools in Texas (Grunbaum et al. 2000). 

It should be emphasised that it is not appropriate to identify participants for targeted interventions solely based on the existence of these factors, as the relationship between these factors and drug use is probabilistic (Frisher et al. 2005). It should be noted that risk factors can differ in importance across individuals or groups and risk factors and can change over the course of development (Pandina 1996). Another important characteristic of risk factors is that their effect is cumulative or synergetic and the presence of a single risk factor cannot adequately predict later drug use (National Drug Research Institute and the Centre for Adolescent Health in Australia 2004). However, it cannot be assumed that drug use is caused by a simple added result of these factors. Their negative effects can be moderated by ‘protective’ factors (Haines & Case 2005; National Drug Research Institute and the Centre for Adolescent Health in Australia 2004).  

To conclude, certain risk factors, current cannabis use and being part of vulnerable groups have been associated with Class A drug use. However, it should be noted that none of the factors can accurately identify those who are contemplating to the use of Class A drugs. The decision requires an individual to want to use a particular drug because s/he expects the drug to fulfil certain positive but not negative functions. Also, s/he has to have an access and resources to obtain and use the drug. The decision to initiate the use of a particular drug appears to be one of complex behavioural choice, which are largely determined by an interaction of psychological, environmental and biological factors.  

References 

Becker J, Roe S (2005) Drug use among vulnerable groups of young people: Findings from the 2003 Crime and Justice Survey. Home Office, London. 

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Morral AR, McCaffrey DF, Paddock SM (2002) Reassessing the marijuana gateway effect. Addiction. 97:1493-1505 

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Sumnall HR, Tyler E, Wagstaff GF, Cole JC (2004) A behavioural economic analysis of alcohol, amphetamine, cocaine, and ecstasy purchases by recreational polydrug users. Drug and Alcohol Dependence, 76(1): 93-99. 

The Child and Adolescent Health Research Unit (2004) Scottish schools adolescent lifestyle and substance use survey 2004: Interim report. Information and Statistics division, NHS, Scotland. 

The National Drug Research Institute and the Centre for Adolescent Health. Monograph. The prevention of substance use, risk and harm in Australia: A review of the evidence.  Commonwealth of Australia, Australia. 2004. 

Vuchinich RE, Heather N (2003) Choice, behavioural economics and addiction. Oxford, Elsevier Science Ltd.