New research tracking more than 40,000 people prescribed opioid agonist treatment in Scotland has found that illicit benzodiazepine use is one of the strongest predictors of drug related death. The risk holds whether someone is currently in treatment or has recently stopped. Published in the International Journal of Drug Policy, the study was led by researchers at Glasgow Caledonian University and Public Health Scotland, who followed the cohort between 2015 and 2020. Their findings point to a growing street market as the real driver of harm, rather than the medicines doctors prescribe.

Opioid agonist treatment, using methadone or buprenorphine, is one of the most effective tools available for reducing deaths among people dependent on opioids. But the study set out to answer a question that has troubled clinicians for years. Does adding a benzodiazepine, whether prescribed or bought on the street, tip that balance the wrong way.

A Decade of Numbers That Tell Two Different Stories

Researchers followed 40,753 people over 189,202 person years. They recorded 3,159 drug related deaths, a crude rate of 16.7 per 1,000 person years. Around 40 per cent of the cohort were prescribed a benzodiazepine such as diazepam at some point during follow up.

When the team looked only at prescribed benzodiazepines, the picture was reassuring on the surface. Overall, there was no clear increase in death rates linked to prescribing. During periods when people stayed actively engaged in opioid agonist treatment, prescribed benzodiazepines showed no added risk at all. The danger appeared only once someone had stopped treatment. Among that group, the death rate for people still taking a prescribed benzodiazepine climbed to 57.5 per 1,000 person years. That compares with 34.5 among those who were not.

Unprescribed benzodiazepines told a starker and more consistent story. Among the 25,870 people with a linked drug treatment assessment record, more than a third reported using an unprescribed benzodiazepine at baseline. This pattern of illicit benzodiazepine use was associated with a 60 per cent higher rate of drug related death overall. Crucially, the risk held steady whether someone was on treatment or had recently come off it. The adjusted rate rose by 64 per cent while in treatment and 57 per cent outside it.

The Street Market Behind the Toxicology Reports

Scotland’s benzodiazepine problem has changed shape over the past decade. Diverted prescription medicines such as diazepam have been steadily replaced by counterfeit tablets manufactured to look identical. Most commonly, these contain etizolam. These so called street benzos vary wildly in strength and ingredients. Users are frequently unaware of exactly what they have taken.

Post mortem toxicology in the study bears this out. Detection of prescribable benzodiazepines at death fell over the study period. Meanwhile, detection of non prescribable substances rose sharply, appearing in around three quarters of recent deaths where any benzodiazepine was found. Toxicology and self reported illicit benzodiazepine use did not always line up either. Non prescribable benzodiazepines turned up in the bodies of some people who had never reported illicit use. That is a sign this kind of exposure is likely under recorded rather than overstated.

Why Retention in Treatment Still Matters Most

The findings sharpen rather than settle the long running debate over prescribing benzodiazepines alongside opioid agonist treatment. Clinical guidance has urged caution since 2017, largely on the assumption that co prescribing itself carries risk. This study suggests the greater danger lies elsewhere. Prescribed medicines, taken as directed and alongside consistent contact with treatment services, were not the main problem here. The sharpest rise in deaths came when people left treatment altogether. And illicit benzodiazepine use proved dangerous in every circumstance the researchers examined.

That points toward a familiar conclusion for anyone working in this field. The most protective factor is not which medicine a person happens to be prescribed. It is whether they remain connected to treatment and shielded from an unregulated and increasingly unpredictable drug supply. Keeping people engaged matters. So does cutting off demand for unprescribed benzodiazepines before it takes hold.

The authors are cautious about overclaiming a solution. They note that self reported illicit benzodiazepine use is difficult to measure precisely. A UK clinical trial into supervised benzodiazepine prescribing is now under way in Scotland and England. Until firmer answers arrive, the study’s message is straightforward. The greatest risk to people on opioid agonist treatment does not come from the medicines cabinet. It comes from the street.

Source: dbrecoveryresources