People who experienced stronger subjective effects from cannabis were more likely to develop heavy use, abuse, and dependence, even after accounting for genetic and environmental risk factors.
Read this if you are curious whether how cannabis affects you personally predicts your risk for developing problems with it.
High responders were 3-12x more likely to become heavy users, independent of genetic risk
What the researchers found
Using data from 464 cannabis-using offspring of twins from the Vietnam Era Twin Registry, researchers identified four classes of subjective response to cannabis: high responders (39%), positive responders (28%), mixed/relaxed (22%), and low responders (11%).
Compared to low responders, all other groups used more heavily (odds ratios 3.0 to 11.8). High responders were significantly more likely to develop cannabis abuse and dependence compared to mixed/relaxed and positive responders.
Critically, these associations persisted after adjusting for familial (genetic and shared environmental) risk for substance use disorders, psychopathology, and demographics. This means the way cannabis affects you subjectively predicts your risk above and beyond your genetic vulnerability.
Why it matters
Identifying individual risk factors for cannabis dependence beyond genetics is important for prevention. If how you respond to cannabis the first few times predicts later problems, this could be a useful screening tool.
The numbers in context
464 cannabis users analyzed. Four response classes: high (39%), positive (28%), mixed/relaxed (22%), low (11%). Heavy use ORs vs low responders: 3.0-11.8. High responders had greatest abuse/dependence risk.
How the study worked
Offspring-of-twins design using 725 twin members of the Vietnam Era Twin Registry, 839 biological offspring (ages 12-32), and 427 mothers. Latent class analysis identified four groups based on 13 subjective cannabis effects. Logistic regression tested associations with use severity, controlling for familial risk.
What this study cannot tell us
Retrospective recall of subjective effects may be influenced by later use patterns. The twin-offspring design controls for many confounds but cannot fully establish causation. The classification of "high responders" may partly reflect heavier use rather than purely predicting it.
How to read the evidence
Twin-offspring design with strong genetic controls. Retrospective subjective recall is a limitation. Moderate sample size.
When this study was published
Published in 2009. The relationship between subjective drug response and addiction risk has continued to be validated across substances.
The bigger picture
Similar findings exist for alcohol: people who experience stronger effects from early drinking are more likely to develop alcohol problems. This study extended that principle to cannabis, suggesting a common vulnerability marker across substances.
Questions still open
- Could subjective response screening identify at-risk individuals before problems develop? Is the subjective response pattern heritable separately from addiction vulnerability? Do subjective effects change with tolerance?
Common questions
What does it mean to be a "high responder"?
If I feel strong effects from cannabis, am I at risk?
Read the original research
Subjective effects to cannabis are associated with use, abuse and dependence after adjusting for genetic and environmental influences.
Drug and alcohol dependence, 105(1-2), 76-82
Citation
Scherrer, Jeffrey F; Grant, Julia D; Duncan, Alexis E; Sartor, Carolyn E; Haber, Jon R; Jacob, Theodore; Bucholz, Kathleen K. (2009). Subjective effects to cannabis are associated with use, abuse and dependence after adjusting for genetic and environmental influences.. Drug and alcohol dependence, 105(1-2), 76-82. https://doi.org/10.1016/j.drugalcdep.2009.06.014
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