Street benzodiazepines pose a greater and more persistent threat to people in drug treatment than prescribed versions. A landmark Scottish study, published in the International Journal of Drug Policy in June 2026, reached this conclusion after tracking more than 40,000 people receiving opioid agonist treatment (OAT) across Scotland between 2015 and 2020. People who reported using illicit benzodiazepines faced a 60% higher rate of drug-related death. That elevated risk held whether or not they were actively in treatment at the time.

The findings land at a critical moment. Drug-related deaths in Scotland rank among the highest in Europe. Street benzos now appear routinely in post-mortem toxicology reports. Non-prescribable benzodiazepines were implicated in more than 60% of drug-related deaths in Scotland between 2015 and 2022, most of them alongside opioids.

What Illicit Benzodiazepine Use Does to Death Rates

Researchers at Glasgow Caledonian University and Public Health Scotland linked prescribing, specialist drug treatment, and national mortality records. They examined how benzodiazepine exposure, both prescribed and illicit, affects death rates among people on methadone or buprenorphine.

The cohort recorded 3,159 drug-related deaths over 189,202 person-years of follow-up. The crude overall death rate was 16.7 per 1,000 person-years. Among those in the cohort, 40% received a benzodiazepine prescription at some point during the study period.

Prescribed benzodiazepines told a more complicated story. While people were actively on OAT, a prescription carried little additional risk of death. The adjusted incidence rate ratio was 0.89, statistically below the threshold of harm. When people stopped OAT, however, having a prescription sharply raised the risk. Death rates reached 57.5 per 1,000 person-years among those prescribed benzodiazepines while off treatment, against 34.5 among those without a prescription. That translates to a 55% higher death rate.

Illicit benzodiazepines produced a consistently worse picture. On OAT, illicit users faced a 64% higher death rate than non-users. Off treatment, their excess risk sat at 57%. Unlike prescribed benzodiazepines, illicit use raised the risk of death at every stage of the treatment journey.

The Hidden Danger of Street Benzos

Street benzos in Scotland typically take the form of illicitly manufactured tablets containing etizolam, a substance with no UK prescription licence. Manufacturers design them to resemble pharmaceutical diazepam. Users often have no idea what they are taking or at what dose, and that uncertainty is part of what makes street benzodiazepines so dangerous.

Post-mortem toxicology data from the study show how sharply the illicit drug supply shifted across the six years. Detection of etizolam at death climbed steeply. Detection of prescribable diazepam fell. By 2018 to 2020, non-prescribable benzodiazepines turned up in 75% of drug-related deaths among those who had reported illicit use, but they also appeared in 73% of deaths among those who had not reported illicit benzodiazepine use at baseline.

That near-convergence points to one clear conclusion. Illicit benzodiazepine use had spread far beyond what self-reported figures suggested. The European Union Drugs Agency was already monitoring more than 30 variants of novel designer benzodiazepines in 2021, and new formulations continued to appear.

Staying in Treatment Saves Lives

Remaining on OAT makes a substantial difference. Death rates during off-treatment periods exceeded 36.8 per 1,000 person-years. During active treatment, that figure dropped to 10.4. Treatment more than triples the chance of survival in any given year.

Prescribed benzodiazepines raised death risk mainly in those who had already left OAT. That raises important questions. When people stop treatment, what happens to their prescriptions? Do the drugs they were given for anxiety or sleep disorders become part of a more dangerous pattern of use without the structure of supervised treatment around them?

Earlier Scottish research by Best and colleagues found a comparable adjusted death rate ratio of 1.14 associated with benzodiazepine co-prescription, confirming that the effect is real and not an artefact of this study alone. A Canadian study also found that people using non-prescribed benzodiazepines showed lower OAT retention than those receiving prescriptions, suggesting that a supervised prescribing model may actually help some patients stay in treatment longer.

Illicit Benzodiazepines Demand a Stronger Policy Response

UK clinical guidelines from 2017 advise caution when co-prescribing benzodiazepines alongside OAT. Those guidelines predate the full emergence of the illicit street benzodiazepine crisis. Researchers argue that clinicians now need to weigh the risks and benefits more carefully, taking into account whether a patient already uses street drugs.

Scotland’s Medication Assisted Treatment (MAT) standards offer one framework for doing this. They combine pharmacological treatment with psychological support and harm reduction. The question is whether a regulated, supervised prescribing approach could reduce harm from illicit benzodiazepine use for people at highest risk.

A randomised clinical trial of benzodiazepine prescribing for people in OAT is now running in both Scotland and England. That trial may eventually provide clearer answers. For now, the evidence points to two priorities: address illicit benzodiazepine use directly, and keep people in treatment for as long as possible.

Source: dbrecoveryresources