Most high-risk drug users substituted their preferred drug with another, with synthetic cannabinoids replacing cannabis in 33% of cases | Research

The takeaway

Among 592 high-risk drug users in treatment, 75.7% reported substituting their preferred drug, with 33.5% of cannabis users switching to synthetic cannabinoids and 35.9% of heroin users switching to street methadone.

Addiction treatment clinicians, drug policy makers, and harm reduction workers.

75.7% substituted drugs; 33.5% of cannabis users switched to synthetic cannabinoids

What the researchers found

448 of 592 high-risk drug users (75.7%) reported substituting their preferred drug. Cannabis users most commonly substituted synthetic cannabinoid receptor agonists (33.5%) followed by alcohol (16%). Heroin users most commonly substituted street methadone (35.9%) followed by prescription opioids (17.7%). Age at onset, education, and treatment setting predicted substitution patterns.

Why it matters

Drug substitution is a clinical reality that treatment programs rarely address. When cannabis is unavailable, users may switch to more dangerous synthetic cannabinoids. Understanding these patterns helps predict risks when supply is disrupted.

The numbers in context

592 users; 75.7% reported substitution; cannabis→synthetic cannabinoids 33.5%; cannabis→alcohol 16%; heroin→street methadone 35.9%; heroin→prescription opioids 17.7%.

How the study worked

Cross-sectional interviews with 592 high-risk drug users in pharmacological and psychosocial treatment, assessing lifetime substitution patterns for heroin and cannabis using descriptive statistics and multinomial logistic regression.

What this study cannot tell us

High-risk treatment population (may not represent casual users); Israeli sample (drug availability differs from US/Europe); self-report of substitution; retrospective; cannot determine health outcomes of substitution.

How to read the evidence

Moderate: reasonable sample with clinical population, but cross-sectional and self-report.

When this study was published

Published 2020.

The bigger picture

The high rate of cannabis-to-synthetic-cannabinoid substitution has direct policy implications: restricting cannabis access without addressing synthetic alternatives may push users toward more dangerous products.

Questions still open

Would cannabis legalization reduce synthetic cannabinoid use? Should treatment programs screen for substitution behavior to prevent escalation?

Common questions

What do cannabis users switch to when cannabis is unavailable?

In this high-risk population, 33.5% of cannabis users substituted synthetic cannabinoids (which are more potent and dangerous), followed by alcohol (16%). This suggests restricting cannabis access may inadvertently push users toward riskier substances.

Is drug substitution common?

Very. Over three-quarters (75.7%) of high-risk drug users reported substituting their preferred drug for another substance at some point, driven by cost, availability, safety perceptions, and legal concerns.

Read the original research

The switch from one substance-of-abuse to another: illicit drug substitution behaviors in a sample of high-risk drug users.

PeerJ, 8, e9461

View on PubMed ↗Publisher’s paper ↗

Citation

Shapira, Barak; Rosca, Paola; Berkovitz, Ronny; Gorjaltsan, Igor; Neumark, Yehuda. (2020). The switch from one substance-of-abuse to another: illicit drug substitution behaviors in a sample of high-risk drug users.. PeerJ, 8, e9461. https://doi.org/10.7717/peerj.9461