Jamaican cannabis THC levels surged from 1% to over 10% between 2014 and 2020 | Research

The takeaway

Analysis of 299 cannabis samples from across Jamaica found a dramatic increase in THC potency from a median of 1.1% in 2014 to 10.2% in 2020, with THC-to-CBD ratios jumping from 2:1 to 194:1.

Drug policy researchers, Caribbean public health officials, and cannabis potency monitoring programs

THC: 1.1% to 10.2%; THC:CBD ratio: 2:1 to 194:1

What the researchers found

Median total THC increased significantly from 1.1% in 2014 to 10.2% in 2020 (p < 0.05). THC-to-CBD ratios increased from 2.1 in 2014 to 194.1 in 2020, indicating virtual elimination of CBD content. The highest median THC was detected in Manchester parish (21.1%). Freshness indicators improved, suggesting samples were of higher quality.

Why it matters

Jamaica is a major cannabis-producing country. The dramatic potency increase has implications for health outcomes, as higher THC and lower CBD content is associated with greater psychosis risk and dependence potential.

The numbers in context

299 samples from 12 parishes; median THC: 1.1% (2014) to 10.2% (2020); THC:CBD ratio: 2.1 (2014) to 194.1 (2020); highest parish median: Manchester at 21.1%; improved freshness (CBN/THC <0.013)

How the study worked

Analysis of 299 herbal cannabis samples received from 12 parishes across Jamaica during 2014-2020. Major cannabinoid levels were determined using gas chromatography-mass spectrometry. THC, CBD, and CBN levels were quantified to assess potency and freshness.

What this study cannot tell us

Convenience sampling from available samples, not random population sampling; 299 samples over 7 years may not represent all cannabis in Jamaica; cannot determine if potency increase reflects cultivation changes or sample selection; no user outcome data

How to read the evidence

Systematic chemical analysis of samples from multiple parishes, but convenience sampling and relatively small sample size limit population-level conclusions.

When this study was published

2024 publication analyzing 2014-2020 samples

The bigger picture

The global trend of increasing cannabis potency is now confirmed in Jamaica, a country with deeply rooted cannabis culture. The near-elimination of CBD from the THC-to-CBD ratio is particularly concerning given CBD's potential moderating effects on THC.

Questions still open

Is the potency increase driven by imported cultivation techniques or local breeding? Are Jamaican cannabis users aware of the dramatic potency increase? How has this affected rates of cannabis-related health problems in Jamaica?

Common questions

How much has Jamaican cannabis potency changed?

Dramatically. Median THC content increased nearly tenfold from 1.1% in 2014 to 10.2% in 2020. Some areas had even higher levels, with Manchester parish showing a median of 21.1% THC.

Why does the THC-to-CBD ratio matter?

The ratio increased from 2:1 to 194:1, meaning modern Jamaican cannabis has virtually no CBD. CBD may moderate some negative effects of THC, including psychosis risk. The near-elimination of CBD from the plant makes today's Jamaican cannabis fundamentally different from what was traditionally consumed.

Read the original research

Potency trends of cannabis in Jamaica during the period of 2014 to 2020.

Drug testing and analysis, 16(2), 174-186

View on PubMed ↗Publisher’s paper ↗

Citation

Lindsay, Carole M; Bernard, Khalia K; Hammond, Amanda M; Beckford, Sheldon; Abel, Wendel D; Brown, Paul D; Young, Lauriann E. (2024). Potency trends of cannabis in Jamaica during the period of 2014 to 2020.. Drug testing and analysis, 16(2), 174-186. https://doi.org/10.1002/dta.3527