Karl W. Hillig, a graduate student in the laboratory of long-time Cannabis researcher Paul G. Mahlberg[77] at Indiana University, conducted a systematic investigation of genetic, morphological, and chemotaxonomic variation among 157 Cannabis accessions of known geographic origin, including fiber, drug, and feral populations. In 2004, Hillig and Mahlberg published a chemotaxonomic analysis of cannabinoid variation in their Cannabis germplasm collection. They used gas chromatography to determine cannabinoid content and to infer allele frequencies of the gene that controls CBD and THC production within the studied populations, and concluded that the patterns of cannabinoid variation support recognition of C. sativa and C. indica as separate species, but not C. ruderalis.[52] The authors assigned fiber/seed landraces and feral populations from Europe, Central Asia, and Turkey to C. sativa. Narrow-leaflet and wide-leaflet drug accessions, southern and eastern Asian hemp accessions, and feral Himalayan populations were assigned to C. indica. In 2005, Hillig published a genetic analysis of the same set of accessions (this paper was the first in the series, but was delayed in publication), and proposed a three-species classification, recognizing C. sativa, C. indica, and (tentatively) C. ruderalis.[55] In his doctoral dissertation published the same year, Hillig stated that principal components analysis of phenotypic (morphological) traits failed to differentiate the putative species, but that canonical variates analysis resulted in a high degree of discrimination of the putative species and infraspecific taxa.[78] Another paper in the series on chemotaxonomic variation in the terpenoid content of the essential oil of Cannabis revealed that several wide-leaflet drug strains in the collection had relatively high levels of certain sesquiterpene alcohols, including guaiol and isomers of eudesmol, that set them apart from the other putative taxa.[79] Hillig concluded that the patterns of genetic, morphological, and chemotaxonomic variation support recognition of C. sativa and C. indica as separate species. He also concluded there is little support to treat C. ruderalis as a separate species from C. sativa at this time, but more research on wild and weedy populations is needed because they were underrepresented in their collection.

Epidiolex is the first FDA-approved treatment in the U.S. that contains a purified drug substance derived from marijuana -- CBD -- and the first treatment for Dravet syndrome. In September 2018 the FDA rescheduled cannabidiol from a C-I controlled substance to a C-V controlled substance, meaning it has a proven medical use but a low risk of abuse. This change allows Epidiolex to be marketed in the U.S.

In 1937, the Marijuana Tax Act strictly regulated the cultivation and sale of all cannabis varieties. The Controlled Substances Act of 1970 classified all forms of cannabis — including hemp — as a Schedule I drug, making it illegal to grow it in the United States (which is why we’re forced to import hemp from other countries as long as it contains scant levels of THC — 0.3% is the regulation for hemp cultivation in the European Union and Canada). As a result of this long-term prohibition, most people have forgotten the industrial uses of the plant and continue to misidentify hemp with its cannabis cousin, marijuana.
Soil characteristics, latitude and climatic stresses have been found to have significant effects on THC concentrations, and there are seasonal and even diurnal variations (Small 1979; Pate 1998b). However, the range of THC concentrations developed by low-THC cultivars (those typically with £0.3% THC) under different circumstances on the whole is limited, for the most part generally not varying more than 0.2 percentage points when grown in a range of circumstances, and usually less (note information in Scheifle et al. 1999; Scheifle 2000, Scheifle and Dragla 2000). Practically, this has meant in Canadian experience that a few cultivars have been eliminated from further commercial cultivation because they sometimes exceed the 0.3% level (‘Fedora 19’ and ‘Futura,’ authorized in 2000, have now been removed because some test results in several years exceeded 0.3%; ‘Finola’ and ‘Uniko B’ are under probation because of elevated levels), but on the whole most of the permitted cultivars have maintained highly consistent development of quite low levels of THC.
Did you get an answer for this? I have the exact same scenario. I'm treating my TN with Tegretol, and recently tried CBD. I think I took too much and there are some weird drug interactions with Tegretol and I felt quite stoned....was alone and talking to myself in my head thinking I was Einstein. It freaked me out a bit but I think I took too much. I'm trying lower doses again as recently my TN seems to be resisting the meds, although I have had a lot of emotional stress, which seems to be a trigger. Thanks!! Anna