Is it possible to define a dose at which cannabis use becomes abuse?

At what point does cannabis use cease to be occasional and become problematic? This question, which has long been addressed in vague terms, is the subject of an attempt to provide a quantitative answer in a scientific study published in January 2026 in the journal Addiction.

For the first time, researchers are proposing weekly THC consumption thresholds associated with an increased risk of cannabis use disorder (CUD), taking into account age and the actual amount consumed.

Cannabis Use Disorder: An Underestimated Public Health Issue

The Cannabis is now the the most commonly used illicit substance in Europe. According to estimates, between 10 and 22% Some people who use cannabis will develop a cannabis use disorder at some point in their lives.

The cannabis addiction is characterized by a loss of control over use, increased tolerance, continued use despite negative consequences, and difficulties in fulfilling professional, academic, or social obligations.

Despite its impact, this disorder remains largely underdiagnosed and not widely supported, particularly in countries where it is illegal. Most of the people affected do not seek professional help, preferring self-regulation or informal solutions. In this context, the lack of clear quantitative benchmarks The lack of attention to levels of risky consumption represents a blind spot in risk-reduction policies.

Why Frequency Alone Is No Longer Enough to Assess Risk

Until now, the recommendations have been based primarily on the consumption frequency : occasional, regular, or daily use. However, this approach no longer reflects the reality of current practices.

The product performance has improved significantly in recent decades, as consumption patterns have diversified. Resins, highly concentrated flowers, extracts, concentrates, or blends: two people who use cannabis the same number of days per week may ingest radically different amounts of THC.

The researchers explain that the amount of THC ingested, combined with the strength of the product, plays a decisive role in the risk of developing a CUD, regardless of the number of days of use.

THC units: a new measurement tool

To overcome these limitations, the study draws on a concept now widely used in international research: the’standard unit of THC, defined as 5 milligrams of delta-9-tetrahydrocannabinol. This approach aims to provide an equivalent to the units of alcohol, which have long served as the basis for public health recommendations.

The advantage of this method is that it allows for a Comparison of Different Products and Consumption Patterns, focusing on the psychoactive molecule itself rather than on the form in which it is consumed.

The data analyzed comes from the study CannTeen, conducted in London over a 12-month period. The researchers followed 150 participants who had used cannabis at least once during the year, divided into two groups:

• from teenagers aged 16 to 17,
• from adults aged 26 to 29.

Consumption was assessed every three months using a detailed tool that took into account the quantity, the frequency, the product type and the estimated power. At the end of the study, participants were evaluated according to the clinical criteria of the DSM-5 in order to determine the presence and possible severity of a cannabis use disorder.

Consumption thresholds associated with the risk of CUD

The results show a the high ability of THC units to discriminate people with a CUD compared to those without one. Weekly thresholds were thus identified.

Among the adults, the risk increases significantly starting at:

• 8.26 units of THC (40 mg) per week for mild to severe CUD,
• 13.44 units of THC (65 mg) per week for moderate to severe CUD.

Among the teenagers, the thresholds are lower:

• 6.04 units (30 mg) per week for any CUD level,
• 6.45 (32 mg) units per week for moderate to severe cases.

These figures reflect a increased vulnerability among adolescents : The transition from mild problematic use to a more severe disorder appears to occur at very similar levels of consumption.

Adolescents and Adults and THC: Different Risks

One of the study’s major contributions lies in the distinction between age groups. In adults, a relatively gradual dose-response relationship is observed: as the amount of THC increases, the risk and severity of CUD also increase.

Among adolescents, however, the margin of safety appears to be extremely narrow. The thresholds for a mild disorder and a more severe disorder are nearly identical, suggesting that a moderate increase in consumption can quickly lead to significant clinical consequences.

These results reinforce the idea that the developing brain is particularly sensitive to the effects of THC, a fact that has already been extensively documented in the scientific literature.

A prevention tool, not a consumption standard

The authors emphasize that these thresholds do not constitute nor authorization, nor are they a guideline for “acceptable consumption.” They should not be used as diagnostic criteria, but rather as risk indicators.

The primary goal is to provide risk reduction tools for people who already use cannabis and want to reduce their risk of developing CUD. Reducing THC intake can be achieved by lowering the dose, spacing out use, or choosing less concentrated products.

As the researchers point out, The only way to eliminate risk is to abstain from consumption, especially among adolescents.

Toward Future Public Health Recommendations?

This study constitutes a first step toward the development of quantitative recommendations on cannabis use, comparable to those that exist for alcohol. It also highlights the need to integrate the product performance, theage of consumers and consumption patterns in public policy.

Further research, conducted on larger populations and in different legal contexts, will be needed to refine these thresholds.