Ecstasy and the antecedents of illicit drug use

Ecstasy (3-4 methylenedioxymethamphetamine, MDMA) is a synthetic, psychoactive drug chemically similar to the stimulant methamphetamine and the hallucinogen mescaline. It is neurotoxic for animals and a health risk for humans.¹ Most users are young, and use has increased in most European countries where annual survey data are available, now exceeding amphetamine use in some. In Europe recent lifetime experience rates range from 0.4% to 13% among 15-24-year olds; in the United States the rate is 14.8% among 18-25 year olds.² However, surveys probably underestimate the number of users.³ Ecstasy users often use other illicit drugs,⁴ raising the question why young people take addictive drugs.

To become addicted to something, you must first be able to obtain it; then you have to try it, you must instantly like it or learn to like it, you must start to think that you need it, and you must like the rewards more than you dislike the punishments. Late childhood and early adolescence is the most dangerous time, when contacts outside the family increase and socialising with friends becomes more important. Peers and pushers can encourage experimentation with drugs, and experienced users may teach and encourage continued use. Those with mental health problems may be at increased risk of regular use and addiction. Emotional and behavioural problems have repeatedly been found to be associated with and to predict substance misuse.⁵,⁶ Children with such problems tend to be impulsive, hyperactive, aggressive, and delinquent; have short attention spans; and resort to truancy and antisocial behaviour.

However, young people with anxiety or depression tend to have fewer friends and social contacts than their normally developing peers and are therefore less often exposed to drug use in adolescent subcultures. Many studies have found no association between these disorders and later risk of illicit drug use or addiction. Now, however, Huizink and colleagues report that Dutch adolescents with symptoms of anxiety or depression in childhood are at increased risk of using ecstasy (p 825).⁷ As they note, ecstasy may be especially appealing to young people with anxiety or depression because it can cause feelings of relaxation, euphoria, and friendship. This “love drug” may appeal to a youth group that would otherwise be less interested in drug use.

Causal influences in drug use are notoriously difficult to identify because cohort studies are burdensome and there are three possible explanations for any association: mood disorders can lead to drug misuse, drug misuse can lead to mood disorders, or both can have a common cause. The third possibility is suggested by twin and adoption studies that show familial clustering of drug use, which could be explained by genetic and environmental factors.⁶,⁸ In Huizink and colleagues' study the fortuitous absence of ecstasy from the Dutch drug scene at the time of the baseline examination of behavioural and emotional problems supports the view that anxiety and depression can encourage subsequent ecstasy use.⁷ Their results thus identify one causal path, but there was also a hint of a second path: delinquent behaviour predicted ecstasy use in the multivariate analysis with all available confounders, but this association disappeared in the final analysis.

It should be noted, however, that only 10% of those with symptoms of anxiety and depression in this Dutch study had five or more occasions of ecstasy use, and the resulting hazard ratio was only 2.22. Studies of substance misuse typically identify many risk factors, but no single dominant one. We cannot solve the problems of drug misuse by eliminating a single risk factor. Preventive efforts must be target many factors. Educational interventions in school are popular, but a recent Cochrane review found only one skills oriented programme that reduced hard drug use.⁹ Unfortunately, ecstasy users often are well aware of the risks of drug use, but do not think themselves to be vulnerable.¹⁰ Prevention should start early. Randomised controlled studies have found that teaching of good parenting skills in early childhood is effective.¹¹ Good mental health services for children also seem important: one US study found that many adolescents entering treatment programmes for substance misuse had untreated mental health problems.¹²