Short answer: A finding about THC, CBD, or one cannabis preparation cannot automatically be applied to every cannabinoid product. A 2019 review of cannabis and the endocannabinoid system explains why: the biology involves multiple compounds, receptors, endogenous ligands, enzymes, tissues, doses, and routes of exposure.
The review describes a signaling network rather than a single switch. It includes endogenous ligands such as anandamide, receptors including CB1 and CB2, and enzymes that synthesize or break down those ligands. The paper also discusses other targets, including TRPV1 and GPR55, whose roles differ from the classic cannabinoid receptors.
CB1 receptors are widely associated with central nervous system signaling. CB2 receptors are prominent in immune-related cells, although receptor distribution and function are more complicated than a simple brain-versus-body division. Exogenous phytocannabinoids interact with this network in different ways.
Delta-9-tetrahydrocannabinol (THC) is principally responsible for the familiar psychotropic effects of cannabis. Cannabidiol (CBD) does not produce the same intoxication profile and engages a broader set of proposed molecular targets. The review also notes that cannabis contains many other constituents. Product composition therefore matters.
In a forensic setting, the label “cannabis” may conceal major differences in THC concentration, CBD content, formulation, dose, timing, and route of administration. A mechanistic observation about purified CBD is not proof of the effect of high-THC flower, an edible, or a synthetic cannabinoid.
The authors summarize proposed antiepileptic, analgesic, anxiolytic, antipsychotic, anti-inflammatory, and neuroprotective properties of CBD. They also emphasize that efficacy, tolerability, and safety findings for cannabinoid-based medicines were inconsistent across conditions and that more evidence was required before broad recommendations could be made.
Sound interpretation begins by identifying the actual analyte and product, not merely the word “cannabis.” The relevant questions include which cannabinoid was present, in what concentration, by what route, at what time, and what outcome was measured. Mechanism evidence can explain plausibility, but it does not by itself establish impairment, causation, or a clinical effect in an individual case.
Millán-Guerrero RO, Isais-Millán S. Cannabis and the exocannabinoid and endocannabinoid systems: use and controversies. Gaceta Médica de México. 2019. PubMed record (PMID 32091020). DOI: 10.24875/GMM.19004881.