Cannabis / THC

Cannabis (marijuana) is a plant whose dried flowers and extracts are used for psychoactive and, in some cases, medical effects. Its principal psychoactive compound is delta-9-tetrahydrocannabinol (THC); it also contains cannabidiol (CBD) and many other cannabinoids. Cannabis is smoked or vaporized, or eaten in edibles, and the potency of today's products — especially concentrates and extracts — is substantially higher than in past decades. While often perceived as low-risk, cannabis can impair coordination, judgment, and memory, can lead to dependence, and can provoke anxiety, panic, or — in vulnerable individuals — psychosis. Its legal status is unusually complicated and currently changing, differing sharply between U.S. federal and state law and from one country to another.

THC acts by binding to cannabinoid receptors (chiefly CB1) that are part of the body's endocannabinoid system — a network helping regulate mood, appetite, memory, coordination, and the perception of pain and pleasure. By activating these receptors, THC alters the system's normal signaling, producing the characteristic changes in perception, mood, and cognition and influencing dopamine pathways tied to reward. The same receptor activity accounts for many of cannabis's effects and side effects, from altered time perception and appetite changes to impaired short-term memory and coordination. Higher-potency products deliver more THC, which can intensify both desired and adverse effects, particularly anxiety and, with heavy or frequent use, the risk of dependence.

Short-term effects commonly include relaxation, altered perception of time and the senses, increased appetite, and talkativeness or giddiness, along with impaired short-term memory, attention, coordination, and reaction time. Less welcome short-term effects include anxiety, panic, paranoia, a racing heart, dizziness, dry mouth, and red eyes; very high doses — especially from edibles, whose delayed onset can lead people to take more — can cause intense anxiety, disorientation, nausea and vomiting, and temporary psychotic symptoms. Impaired coordination and judgment make driving while impaired a real hazard. With regular use, some people develop cannabis use disorder and experience withdrawal — irritability, sleep difficulty, decreased appetite, and craving — on stopping. Long-term, frequent use beginning in adolescence is associated with effects on learning and memory, and heavy use is linked, in vulnerable individuals, to an increased risk of psychotic disorders.

The most common cannabis risks are impairment-related: slowed reaction time and impaired judgment make driving or operating machinery dangerous, and effects can be stronger and longer-lasting than expected — especially with edibles, where delayed onset often leads people to consume more before the first dose takes effect. Higher-potency concentrates raise the chance of acute anxiety, panic, and occasionally temporary psychotic reactions; people with a personal or family history of psychosis face elevated risk. Frequent use can lead to dependence, and cannabinoid hyperemesis syndrome — cycles of severe vomiting — can develop in some long-term heavy users. Cannabis is generally not associated with fatal overdose the way opioids are, but illicit or unregulated products can be contaminated (with other drugs, or harmful additives in some vaping products), and combining cannabis with alcohol or other substances increases impairment. Keeping cannabis products away from children, who can be seriously harmed by accidental ingestion of edibles, matters. For poisoning guidance call Poison Control at 1-800-222-1222; for substance-use support the SAMHSA National Helpline is 1-800-662-4357.

FDA-approved cannabis-derived products exist (e.g., Epidiolex; dronabinol/Marinol, Syndros)

placed in Schedule I in 1970