Nordt C, Stohler R. Incidence of heroin use in Zurich, Switzerland: a treatment case register analysis. The Lancet 2006 367:1830-1834
Dear Colleagues,
This definitive study succinctly refutes the last remaining criticism of harm reduction: whether it encourages drug use. It appears to do precisely the opposite, as these authors report.
Switzerland’s ‘cantons’ have registers of drug treatment approvals going back to the 1970s. It is therefore possible to derive statistically valid measures of the rate of addiction of its citizens over the period when needle services, injecting rooms, methadone treatment, heroin prescription and most recently, buprenorphine treatment were being introduced. Such data reflect the natural history of opiate use through interactions with treatment services such as methadone maintenance treatment (MMT), withdrawal from such treatments, mortality and other demographics.
The canton of Zurich has 1.2 million people (a fifth of the Swiss population) over half being rural. Between 1991 and 2005 about 10,000 patients underwent 24,000 episodes of opiate prescribed treatment (2.4 per person). By 2005 there were 3000 still in treatment and 7000 who had been discharged.
Of those who left treatment in Zurich in 1991-1993, 33% never re-entered treatment, 66% rejoined treatment within 10 years, only 1% returning after a decade. The authors derived a long-term annual abstinence rate of 4%, comparing this with an Australian report of 5% along with others. Each year, the mean age of those in current treatment increased by 9 months, reflecting fewer new entrants and high retention rates.
Importantly, about 50% of Swiss subjects entered methadone treatment within 2 years of starting to use heroin with only small differences depending on sex, age and injector status. This contrasted with an average of 4 years to enter treatment in Italy and probably longer in some other countries. The authors further estimate that at any one time, about 50% of those with problem opioid use are on MMT. With fewer new initiates in Switzerland, they project this figure will rise to 64% by 2010. These figures are comparable with reports from Amsterdam in the 1990s.
Perhaps most crucial are the findings regarding the numbers of Zurich canton citizens taking up heroin for the first time. From around 80 people in 1975, this increased progressively to ~850 new users annually by 1990, only to drop again to ~150 by 2002 at the height of the harm reduction interventions. These included prescription heroin to a small but consistent proportion of maintenance cases.
So we can now quote reliable knowledge that in a modern western country which advocates and practises harm reduction in its most progressive form (apart from decriminalized cannabis) there are not more, but fewer young people availing themselves of the opiate class of drugs. Indeed, we can now say with confidence that harm reduction measures do not “send a message” encouraging drug use. The authors believe that by ‘medicalizing’ addiction, an impression is created that it is unpleasant and undesirable, to be avoided, which is just what has happened.
Comments by Andrew Byrne ..
