This may occur in part due to its ability to partially block the same brain chemical receptor THC binds with. CBD can also inhibit the breakdown of a brain chemical called “anandamide,” which makes us feel happy. Incidentally, anandamide is also found in chocolate and is aptly named after the Sanskrit word meaning “bliss”.
People with certain gene variants seem to be at higher risk. However our understanding of these factors is still limited, and we’re unable to use genetic information alone to determine if someone will or won’t develop psychosis from cannabis use.
Psychotic disorders are severe mental health conditions. They’re characterised by a “loss of contact with reality”, where the individual loses the ability to distinguish what’s real from what’s not. Psychotic symptoms can include visual hallucinations, hearing voices, or pervasive delusional thinking.
There has been a recent global rise in “green fever”, with various jurisdictions either decriminalising or legalising cannabis.
But can’t cannabis also be good for mental health?
But alongside relaxing the rules comes concern about the health implications of cannabis use. We often hear of a link between cannabis use and psychosis. So how strong is the link, and who is at risk?
This compound may actually mimic the presentation of psychotic symptoms, including paranoia, sensory alteration, euphoria, and hallucinations. In laboratory-based research, even healthy people may exhibit increased symptoms of psychosis when given THC compounds, with more severe effects observed in people with schizophrenia.
Ironically, one compound found in cannabis may actually be beneficial in treating psychosis. In contrast to THC, a compound called cannabidiol (CBD) may provide a buffering effect to the potentially psychosis-inducing effects of THC.
What is psychosis?
Furthermore, these studies found a causal link between tetrahydrocannabinol (THC – the plant chemical which elicits the “stoned” experience) and psychosis. This means the link is not coincidental, and one has actually caused the other.
The type of cannabis material being used (or the use of synthetic cannabinoids, known as “spice”) may also increase the risk of psychosis. As mentioned above, this is due to the psychological effects of the chemical THC (one of over 140 cannabinoids found in the plant).
Eighteen healthy adult participants, 17 who were hallucinogen-naive, completed five experimental sessions involving administration of 0, 5, 10, 20, and 30 mg/70 kg psilocybin doses in a controlled and supportive laboratory setting. 5 Drug administration sessions were separated by ∼1 month. Data collected during the 5 mg/70 kg dose is not included in this report.
Subjective effects data from 31 healthy adult participants were collected across two cannabis self-administration studies; one experiment (N=17) evaluated acute doses of orally ingested cannabis in brownies that contained 0, 10, 25, and 50 mg THC, and a second study (N=14), in which H.C. was a participant, examined acute doses of smoked, and vaporized cannabis containing 0, 10, or 25 mg THC. Cannabis plant matter was sourced from and certified by the Drug Supply Program of the National Institute on Drug Abuse (NIDA) to contain 13.4% THC and 0.03% CBD. Dried cannabis was weighed and dispensed in a quantity that was calculated to contain the target dose of THC (e.g., 186.6 mg of cannabis would be vaporized to deliver 25 mg THC). Participants endorsed a history of cannabis use and denied use of cannabis for at least 30 days before study enrollment. Participants were not dependent on or seeking treatment for cannabis or other psychoactive drugs. A minimum of 1 week separated each dose condition to allow for a full washout of doses, and washout was biochemically verified with quantitative urine and blood toxicology tests.
Salvinorin A study
Most case reports describing hallucinations following acute cannabis exposure involve individuals with current psychosis or a family history of psychosis, populations that are known to have an atypical response to cannabis. 12 A growing literature continues to explore the relationship between cannabis use and development of psychosis among individuals with an underlying vulnerability for psychosis. 13–16 While perceptual alterations in healthy individuals during the acute effects of THC have been described, 17,18 empirical reports describing hallucinogen-like effects of cannabis and cannabis constituents in controlled settings and in healthy participants without a family history of psychosis are quite rare.
The following report presents the case of an atypical response to cannabis that included self-reported “hallucinogen-like” effects after inhalation of vaporized cannabis containing THC, but nominal levels of CBD in a controlled laboratory study. To qualitatively investigate the phenomenology of this hallucinogen-like experience, we conducted cross-sectional comparisons of data from this case with archival data obtained from controlled behavioral pharmacology studies of cannabis, the classic hallucinogen psilocybin, and the atypical hallucinogens DXM and salvinorin A.
Hallucinogen effects assessment
H.C. presented as a medically and psychiatrically healthy 30-year-old Caucasian male. He denied a history of significant health and psychiatric conditions and denied a family history of psychosis. He endorsed prior cannabis use, denied a history of any significant adverse effects associated with prior use, and he disclosed that 6 years had passed since he last used cannabis. He reported weekly use of alcohol and caffeine and denied use of nicotine/tobacco products and illicit drugs. He endorsed use of over-the-counter medication as needed for seasonal allergies. During the first three study sessions, he smoked cannabis that contained 0, 10, or 25 mg THC through hand-held pipe. Dose-related subjective drug effects, cardiovascular effects, and impairment on cognitive performance assessments were observed as expected. On the fourth experimental session (as with other experimental sessions), baseline assessments were within normal limits and urine drug screening (for common drugs of abuse) and breath alcohol tests were negative. After consuming a standard low-fat breakfast, the participant self-administered vaporized cannabis that contained 25 mg THC within 10 min (per protocol). Acute drug effects escalated in magnitude for the first 20 min following inhalation. He had difficulty responding to staff inquiries, was unable to complete self-report questionnaires, had difficulty keeping his head up, and appeared to periodically fall asleep or lose consciousness despite encouragement by research staff to stay awake and continue. He was unable to maintain a balanced, steady gait when he walked.