When choosing products containing CBD or THC, it is also important to consider their legality. Both marijuana and THC are included in the U.S. Controlled Substances Act, which means that they are not legal under federal law. As of July 2020, 33 states and Washington, D.C. have enacted policies allowing medical marijuana and products containing THC to be prescribed by a doctor. Some states also allow recreational use of marijuana and THC-containing products.
While cannabis itself has not been FDA approved to treat any condition, there are a few drugs approved by the U.S. Food and Drug Administration (FDA) that contain CBD or THC.
Both THC and CBD are stored in body fat, which means that both can potentially be detected on drug tests for some time after you have stopped using them.
Before choosing a THC or CBD product, it is important to check your state laws to ensure that these products are legal where you live. Federal law mandates that hemp-derived CBD products should contain less than 0.3% THC, but even those trace amounts are still illegal in some states.
Because THC is the main psychoactive substance in marijuana, it can be detected on most standard drug tests. CBD may be detectable as well, but many drug tests are not designed to look for cannabidiol.
However, while these substances appear safe, that does not necessarily mean that you won't experience some unwanted effects. Some adverse effects that have been reported include:
Sourced from marijuana
In more recent years, three other novel receptor candidates, GPR18, GPR19 and GPR55, have been discovered, as well as non-CB1Rs and non-CB2Rs, but knowledge on these systems is incomplete and the discussion on whether or not they meet the criteria to qualify as receptors or channels is ongoing [Mackie and Stella, 2006; Pertwee et al. 2010; Pamplona and Takahashi, 2012]. It is generally established that some endocannabinoids, d-9-THC and several synthetic CB1R/CB2R agonists and antagonists can also interact with a number of non-CB1, non-CB2 GPCRs, ligand-gated ion channels and nuclear receptors (see the recent review by Pertwee and colleagues [Pertwee et al. 2010]). In conclusion, the biochemical mechanisms of this system are far more complex and the discussion on whether any known mammalian channel or non-CB1R/CB2R should be classified as a novel cannabinoid ‘CB3’ receptor or channel is ongoing.
However, only a small minority develop a full-blown psychotic illness in the form of schizophrenia or bipolar disorder, whilst a larger group, ranging from 15% to 50%, experience transient psychotic symptoms of brief duration, from a couple of hours to up to a week, and usually recover without requiring any intervention [Thomas, 1996; Green et al. 2003; D’Souza et al. 2004, 2009; Morrison et al. 2009]. Indeed drug challenge studies with d-9-THC on healthy volunteers have shown a broad range of transient symptoms, behaviours and cognitive deficits ranging from anxiety to psychosis to transient memory disturbance [D’Souza et al. 2004; Curran et al. 2002; Morrison et al. 2009]. The clinical picture of transient psychosis can be indistinguishable from a frank acute psychosis with delusions and hallucinations, except for its short duration.
Cannabinoid 1 and 2 receptors
Normally GPCRs are linked together to form a receptor complex. However, the signalling effects can be complex due to CB1Rs forming heteromers, which can be defined as having different parts such as subunits, with two or more other GPCRs, particularly if they are densely expressed in the same neuron. For instance, a CB1R can form a heteromer with dopamine D2 receptor, or in another instance it can also form a heteromer with two other receptors such as dopamine D2 and adenosine A2A [Navarro et al. 2008]. Interestingly, as a result, ligand bindings can produce unexpected pharmacological effects. For instance, in a heteromer complex, not only the antagonist of CB1R but also the other receptor antagonist can block the inhibitory effect of CB1R agonist. This has been demonstrated by Marcellino and colleagues when the CB1R antagonist rimonabant and the specific A2AR antagonist MSX-3 blocked the inhibitory effect of CB1 agonist on D2-like receptor agonist induced hyperlocomotion in rats [Marcellino et al. 2008]. Receptor heteromers provide better understanding of how these different neurotransmitter systems interact with each other. Compelling evidence for the existence of CB1R heteromers in striatal dendritic spines of striatal GABAergic efferent neurons, particularly at a postsynaptic location, has also been reported [Ferré et al. 2009]. The authors propose that it is likely that functional CB1–A2A–D2 receptor heteromers can be found in the dendritic spines of GABAergic enkephalinergic neurons, where they are highly coexpressed, and their analysis provides new information on the role of endocannabinoids in striatal function, which can be considered as retrograde signals that inhibit neurotransmitter release. Further evidence for the existence of D2 and CB1Rs in ventral striatum is provided by electron microscopy analysis, which confirms the relevance to the rewarding and euphoric, as well as motor effects produced by cannabis, by enhancing dopamine levels particularly in the nucleus accumbens [Pickel et al. 2006]. CB1R expression in the striatum and their role in differential signalling between different developmental stages and sensorimotor and associative/limbic circuits have also been demonstrated in a recent study [van Waes et al. 2012].
Different strengths of street cannabis
These findings suggest that current trends for preferring higher THC content variants carry significant health risks, particularly to those who are susceptible to its harmful effects. Indeed, Morgan and colleagues carried out a study on 120 current users, which included 66 daily and 54 recreational users, whose hair analyses revealed their THC and CBD amounts. The study found that higher THC levels in hair in daily users were associated with increased depression and anxiety, as well as poorer prose recall and source memory [Morgan et al. 2011]. However, higher CBD in hair was associated with lower psychosis-like symptoms and better recognition memory. In relation to people with psychosis, health risks are even higher with stronger variants of the plant. In a recent study of people with a first episode of psychosis, it was found that patients used higher-potency cannabis for longer durations and greater frequency compared with a healthy control group [Di Forti et al. 2009].