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Tetrahydrocannabinol Facts

Cannabinoid; Cannabinoid; Cannabinoid CB1 receptor partial agonist

Description

THC (delta-9-tetrahydrocannabinol) — weed, pot, marijuana — is a cannabinoid of the terpenophenolic class. It activates cannabinoid receptors in the brain, suppressing neurotransmitter release and producing its characteristic shifts in mood, perception, and memory.

Subjective effects include euphoria, appetite stimulation, time alteration, relaxation, and anxiety at higher doses. The experience is defined by its sensitivity to context — the same dose can produce warm calm in one setting and anxious self-consciousness in another.[1]

About 9% of users develop cannabis use disorder, rising to 17% in adolescence;[2] no confirmed human fatality from overdose alone has been recorded.[3][4] The primary danger is psychiatric — daily high-potency use carries an odds ratio of 4.8 for psychotic disorder,[5] amplified by early onset and genetic vulnerability.

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 2 mgLight5 – 10 mgCommon10 – 20 mgStrong20 – 50 mgHeavy50+ mg

Starts in 30 – 90 minLasts 4 – 12 hoursAfter-effects 6 – 24 hours

Body and dependence

Acute toxicity
Low
Chronic toxicity
Moderate
Physical dependence
Moderate
Psychological dependence
Moderate
Withdrawal
Moderate
Compulsive redosing
Low

Tolerance

Builds
Moderate
Fully resets after
28 days
Carries over to
synthetic cannabinoids; endocannabinoids; other CB1 agonists

Effectslikely at a common dose

Perception
Dreaming suppression; Music enhancement; +15 possible, including Spatial disorientation, Vestibular distortion
Body
Abnormal heartbeat; Appetite enhancement; Body high; Dry mouth; Heart rate perception changes; Laughter fits; Motor control impairment; Muscle relaxation; Pain suppression; Sedation; +14 possible, including Dizziness, Insomnia, Nausea
Thinking
Aesthetic enhancement; Cognitive euphoria; Cognitive impairment; Decision impairment; Humor enhancement; Information processing suppression; Memory fragmentation; Memory suppression; Thought connectivity; Thought disorganization; +22 possible, including Analysis suppression, Confusion, Delusions of sobriety
Feeling
Euphoria; +8 possible, including Anxiety, Paranoia, Dysphoria
Self
none likely · 10 possible, including Craving, Depersonalization, Derealization
Time
Time alteration; +2 possible, including Temporal disorientation
Awareness
none likely · 1 possible

Who shouldn't take it

Absolute
Active psychotic disorder or personal/family history of psychotic disorder; Breastfeeding; Pregnancy
Relative
Significant cardiovascular disease; Significant pulmonary disease (combustion route); Active substance use disorder; Significant hepatic impairment; Adolescence (under 18); Operating vehicles or machinery while intoxicated

Combinations60 recorded

Dangerous (11)
Ketamine, DXM, PCP; Opioids; GHB, Baclofen; GHB, GBL; Ibogaine; Local anesthetics; MAOIs; NDRIs (Wellbutrin); Salvia, Ibogaine; SNRIs; Synthetic cannabinoids
Caution (33)
See full page: psychedex.org/substances/thc
Not graded (16)
Not listed never means safe.

Seek help immediately if

Natural cannabis rarely causes a medical emergency — "greening out" is: pale/sweaty skin, dizziness, nausea or vomiting, anxiety or panic, rapid heartbeat, feeling faint — and usually passes with rest.

Seek emergency help for these — far more likely with synthetic cannabinoids ("spice" / K2):

  • Seizures
  • Severe chest pain; very fast or irregular heartbeat
  • Unresponsiveness or extreme drowsiness
  • Severe agitation, aggression, or psychosis
  • Repeated vomiting; difficulty breathing

What to do

  1. Sit or lie them down somewhere calm, cool, and quiet
  2. Reassure them — cannabis panic and "greening out" pass with time
  3. Offer sips of water; a little sugar can help if they feel faint
  4. Recovery position if nauseated, drowsy, or vomiting
  5. Stay with them and monitor
  6. For seizures, chest pain, unresponsiveness, or severe agitation, call emergency services

Natural cannabis "greening out" resolves with rest, calm, and time, with no lasting harm. Synthetic cannabinoids are unpredictable and can cause seizures, cardiac events, kidney injury, and severe agitation that needs emergency care.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Crippa JA, Zuardi AW, Martin-Santos R, Bhattacharyya S, Atakan Z, et al. (2009) Cannabis and anxiety: a critical review of the evidence — Human Psychopharmacology Clinical and Experimental doi:10.1002/hup.1048
  2. [2]
    ^Hasin DS (2017) US Epidemiology of Cannabis Use and Associated Problems — Neuropsychopharmacology doi:10.1038/npp.2017.198
  3. [3]
    ^Herkenham M, Lynn AB, Little MD, Johnson MR, Melvin LS (1990) Cannabinoid receptor localization in brain. — Proceedings of the National Academy of Sciences doi:10.1073/pnas.87.5.1932
  4. [4]
    ^Grotenhermen F (2003) Pharmacokinetics and Pharmacodynamics of Cannabinoids — Clinical Pharmacokinetics doi:10.2165/00003088-200342040-00003
  5. [5]
    ^Di Forti M, Quattrone D, Freeman TP, Tripoli G, Gayer-Anderson C, et al. (2019) The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study. — The Lancet Psychiatry doi:10.1016/s2215-0366(19)30048-3
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