Large New Zealand Survey Finds 60% of Cannabis Users Report Using Less Alcohol and Synthetic Cannabinoids | Research

The takeaway

In a survey of 23,500 New Zealand cannabis users, 60% reported that cannabis led to less alcohol and synthetic cannabinoid use, with substitution patterns varying significantly by age, ethnicity, and location.

Drug policy researchers; harm reduction practitioners.

60% reported cannabis led to less alcohol and less synthetic cannabinoid use

What the researchers found

Sixty percent reported cannabis use led to less alcohol use, 60% to less synthetic cannabinoid use, 44% to less morphine use, and 40% to less methamphetamine use. Cannabis had no impact on LSD, MDMA, or cocaine use for about 70% of co-users. One in five reported cannabis led to more tobacco use. Young adults (21-35) and Maori were more likely to report substitution.

Why it matters

The cannabis substitution debate has real policy implications: if cannabis replaces more dangerous substances for some populations, restriction policies may inadvertently increase harm. This is among the largest studies to document substitution patterns and, critically, to show these patterns differ by demographic group.

The numbers in context

23,500 respondents. 60% reported less alcohol use, 60% less synthetic cannabinoid use, 44% less morphine use, 40% less methamphetamine use. 70% no impact on LSD/MDMA/cocaine. 20% more tobacco use. Young adults (21-35) more likely to substitute for alcohol and methamphetamine. Maori more likely to substitute across multiple substances.

How the study worked

Online convenience survey promoted via Facebook, completed by 23,500 New Zealand respondents. Those who co-used cannabis and any of eight other substances in the same six-month period rated cannabis's impact on their other substance use. Frequency and quantity were compared across groups. Generalized logistic regression modeled predictors.

What this study cannot tell us

Convenience sample recruited via Facebook is not representative of all cannabis users. Self-reported substitution effects may reflect perceived rather than actual changes. Cross-sectional data cannot establish causal direction. New Zealand's drug market may differ from other countries.

How to read the evidence

Moderate: very large sample with detailed demographic analysis, but convenience sampling, self-reported outcomes, and cross-sectional design limit causal conclusions.

When this study was published

2024 study.

The bigger picture

Cannabis policy often assumes a "gateway" model where cannabis leads to more drug use. This large-scale evidence from New Zealand supports an alternative model for many users: cannabis as a substitute that reduces use of potentially more harmful substances, particularly alcohol, opioids, and methamphetamine.

Questions still open

Would cannabis legalization in New Zealand shift substitution patterns? Do the demographic differences in substitution reflect cultural attitudes, access to other substances, or different pharmacological responses?

Common questions

Does cannabis actually replace alcohol use?

In this survey, 60% of co-users reported that cannabis led to less drinking, and those who reported substitution had measurably lower alcohol frequency and quantity. However, self-reported substitution may not capture the full picture, and causation cannot be established from survey data.

Why did Maori report more substitution?

The study found Maori were more likely to report cannabis reducing their use of alcohol, tobacco, methamphetamine, and LSD. This may reflect cultural perspectives on cannabis, different substance use patterns, or varying access to alternatives, though the study did not determine specific mechanisms.

Read the original research

Exploring the substitution of cannabis for alcohol and other drugs among a large convenience sample of people who use cannabis.

Harm reduction journal, 21(1), 192

View on PubMed ↗Publisher’s paper ↗

Citation

Wilkins, Chris; Romeo, Jose; Rychert, Marta; Graydon-Guy, Thomas. (2024). Exploring the substitution of cannabis for alcohol and other drugs among a large convenience sample of people who use cannabis.. Harm reduction journal, 21(1), 192. https://doi.org/10.1186/s12954-024-01111-w