Cannabis use and subclinical psychosis traits were linked phenotypically, with some genetic overlap | Research

The takeaway

Cannabis use and schizotypy (subclinical psychosis traits) were positively correlated across 11 of 12 measured pairs, and one significant genetic correlation was found between social anhedonia and cannabis use frequency.

Psychiatric geneticists studying psychosis risk, researchers investigating cannabis-psychosis relationships, and public health professionals assessing population-level risk factors.

11 of 12 cannabis-schizotypy pairs showed positive correlation

What the researchers found

Positive phenotypic correlations (range 0.05-0.18) were found between 11 of 12 cannabis use and schizotypy trait pairs in UK Biobank. The only significant genetic correlation was negative: social anhedonia was inversely correlated with number of times used cannabis (rg = -0.30), suggesting those genetically predisposed to social anhedonia used cannabis less frequently.

Why it matters

The well-established link between cannabis and full psychotic disorders may extend to subclinical psychosis traits in the general population. Understanding the genetic architecture of this relationship could help identify who is most at risk.

The numbers in context

11 of 12 phenotypic correlations were positive (range 0.05-0.18). Social anhedonia heritability: 0.08. "Ever seen an unreal vision" heritability: 0.35. Genetic correlation between social anhedonia and cannabis use frequency: rg = -0.30.

How the study worked

Phenotypic correlations calculated in UK Biobank. SNP-based heritability estimates and genetic correlations computed using genome-wide association study data. Multiple schizotypy phenotypes and cannabis use variables were analyzed.

What this study cannot tell us

Small genetic sample sizes for some schizotypy measures limited statistical power. UK Biobank participants skew older and healthier than the general population. Self-reported cannabis use and psychosis-like experiences may be underreported.

How to read the evidence

Large population sample (UK Biobank) with genetic analyses, but limited by small subsample sizes for some phenotypes and cross-sectional design.

When this study was published

2020 genetic study. Extends cannabis-psychosis research to subclinical traits and general population genetics.

The bigger picture

If the cannabis-psychosis link extends to subclinical traits in the general population, it could inform screening approaches and help identify individuals who should be more cautious about cannabis use.

Questions still open

Does the negative genetic correlation with social anhedonia mean that some genetic factors protect against both traits? Would larger samples reveal additional genetic overlaps? How do these findings apply to younger populations with more active cannabis use?

Common questions

What is schizotypy?

Schizotypy refers to subclinical personality traits that resemble milder forms of psychosis symptoms, such as unusual perceptual experiences, social withdrawal, and magical thinking. These traits exist on a spectrum in the general population.

What does the negative genetic correlation mean?

The genetic factors associated with social anhedonia (reduced pleasure from social interaction) were inversely associated with cannabis use frequency, meaning people genetically predisposed to social withdrawal tended to use cannabis less often.

Read the original research

Exploring Phenotypic and Genetic Overlap Between Cannabis Use and Schizotypy.

Twin research and human genetics : the official journal of the International Society for Twin Studies, 23(4), 221-227

View on PubMed ↗Publisher’s paper ↗

Citation

Vaissiere, James; Thorp, Jackson G; Ong, Jue-Sheng; Ortega-Alonzo, Alfredo; Derks, Eske M. (2020). Exploring Phenotypic and Genetic Overlap Between Cannabis Use and Schizotypy.. Twin research and human genetics : the official journal of the International Society for Twin Studies, 23(4), 221-227. https://doi.org/10.1017/thg.2020.68