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Marijuana Today vs. Marijuana From the ’70s: Is There a Difference in Ohio?

Is today’s cannabis really more potent than it was in the 1970s? There is a lot of speculation about this, and while some research seems to support this claim, there are questions about testing methods, the quality of the materials obtained for the studies, and other issues. Our Ohio Medical Cannabis Doctors can address your concerns regarding potency, dose, route, and other questions you might have. Interested in becoming a medical cannabis patient? Take a quick eligibility survey to see if you pre-qualify. 

According to some recently published studies, today’s cannabis contains between 3-10X more THC than what was available in the middle of the 20th century. They also relate a decrease in the amount of CBD in plants, which leads to a wider gap in the CBD:THC ratio. However, there have been valid concerns raised regarding testing methods, the source and age of the samples used, and the accuracy of the results obtained in these research projects.

One study used cannabis seized by the DEA between 1995-2014. Samples were tested using gas chromatography and flame ionizer detection. Results showed an increase in the potency of illegal plant material from approximately 4% to around 12%. CBD content decreased from ~0.28% to ~0.15%; this changed the THC:CBD ratio in the plant matter studied from 1:14 to ~1:80. (1)

While these results may seem credible because it was a federally-endorsed study, it is important to take several other factors into account before making any assumptions regarding their validity.


  • Even the Federal Government has acknowledged the shortcomings in their testing methods. Potentially concerning factors include how they source the product used in their studies, the effect a large seizure and the testing of that sample affects the results, and the quality of domestic crops seized and tested. 
  • Some of the plant product tested was 20 years old. As time passes, THC degrades into CBN, which can lead to artificially low potency results. 
  • Early cannabis was often smuggled from Columbia and Mexico. “Dirt weed,” as it was called, included stems, seeds, flowers, and other plant matter. What people buy today in the US is often higher quality flower from plants that have been cultivated, trimmed, and grown in a much different environment; dispensary-grade cannabis has been tested in labs for THC/CBD content, potency, and the presence of other chemicals such as toxins or pesticides. (2)
  • The cannabis seized and studied during a particular year may have all come from one region or grower, which could easily skew the results of the test. (3)
  • The testing process was conducted used gas chromatography, which is not the most efficient way to test for THC or CBD levels. The temperature required for testing changes THC-A into THC, and CBD-A into CBD; this means there is no accurate way to tell what proportion of the results comes from THC and CBD and what is the result of heat-stimulated conversion unless researchers first differentiate between the active and inactive or “acid” forms of these cannabinoids. High temperatures can also cause THC degradation, leading to a false low level in the results. (4)
  • It is important to note that the number of samples tested from each year included significant variations, which calls accuracy into question. “In the 1970s, researchers assessed anywhere from three to 18 seizures a year. In 2000, they analyzed more than 1,000 seizures.” (5)
  • There are also variances in the type of plant matter tested. Early tests were performed mostly on cannabis plants referred to at the time as “marijuana,” which includes both male and female flowering types. As time progressed, testing included a higher level of “sensimilla ,” or flowering female plants that have not been pollinated; these contain a higher level of THC. (6) 

There is currently no real way to consistently test the levels of THC, CBD, and other cannabinoids in the wide variety of strains of cannabis currently available on the US market for several reasons:

  • Plants are grown in a variety of climates and growing conditions including indoor and outdoor grows, greenhouse cultivation, and hydroponic facilities.
  • Processing techniques including trimming, drying, curing, and storage. (7)
  • Lab results for a single strain can vary from year to year or even crop to crop depending on the growing environment – source and amount of light, soil quality, the availability of shade, humidity, and watering techniques. (8)


While potency is important, other factors may take precedence for medical cannabis patients. The cannabinoid and terpene profiles in many strains can provide relief for a variety of illnesses and their related symptoms. Even with this knowledge, patients often find they have to do a bit of experimentation to find what works best for them. Different people react to strains in unique ways based on their metabolism, condition, and tolerance. Indica varieties help some patients sleep or relax, while others find it agitates them or triggers PTSD symptoms. People with allergies or certain health conditions may react to terpenes present in some strains. Just as with pharmaceutical medications, cannabis consumers need to look at the whole package (or plant) in order to determine what is best for them. 

In the 70s there was no reliable way to determine the potency or THC content of a specific strain of cannabis without smoking or ingesting it. With the advent of medical and recreational cannabis legalization, many growers now have access to labs capable of testing batches of plants for cannabinoid and terpene content. Processing facilities that make extracts, oils, distillates, and isolates can label their products with relevant information, enabling patients and other consumers to know what they’re getting as well as the effects they can expect. Speaking to a medical cannabis physician can be helpful in making an informed decision about what products to use, how often to use them, and how much to use. 

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4987131/
  2. https://www.originscannabis.com/marijuana-potency/
  3. https://www.mic.com/articles/168922/is-marijuana-stronger-than-it-used-to-be-heres-what-the-science-says
  4. https://www.aocs.org/stay-informed/inform-magazine/featured-articles/the-highs-and-lows-of-cannabis-testing-october-2016
  5. https://www.theatlantic.com/technology/archive/2015/03/was-marijuana-really-less-potent-in-the-1960s/387010/
  6. https://www.ilovegrowingmarijuana.com/types-of-marijuana/
  7. https://www.alchimiaweb.com/blogen/marijuana-growing-guide/harvesting-and-processing/
  8. https://www.oregonlive.com/marijuana/2016/01/our_outdoor_grow_lab_results_a.html