Cannabis has psychoactive and physiological effects when consumed. The minimum amount of THC required to have a perceptible psychoactive effect is about 10 micrograms per kilogram of body weight. Aside from a subjective change in perception and, most notably, mood, the most common short-term physical and neurological effects include increased heart rate, lowered blood pressure, impairment of short-term and working memory, psychomotor coordination, and concentration. Long-term effects are less clear.
Deaths associated to cannabis overdose are exceptionally rare. Fatalities resulting from cannabis overdose are said to most often occur after intravenous injection of hashish oil.
While many psychoactive drugs clearly fall into the category of either stimulant, depressant, or hallucinogen, cannabis exhibits a mix of all properties, perhaps leaning the most towards hallucinogenic or psychedelic properties, though with other effects quite pronounced as well. Though THC is typically considered the primary active component of the cannabis plant, various scientific studies have suggested that certain other cannabinoids like CBD may also play a significant role in its psychoactive effects
Cannabis used medically has several well-documented beneficial effects. Among these are: the amelioration of nausea and vomiting, stimulation of hunger in chemotherapy and AIDS patients, lowered intraocular eye pressure (shown to be effective for treating glaucoma), as well as general analgesic effects (pain reliever).b[›]
Less confirmed individual studies also have been conducted indicating cannabis to be beneficial to a gamut of conditions running from multiple sclerosis to depression. Synthesized cannabinoids are also sold as prescription drugs, including Marinol (dronabinol in the United States and Germany) and Cesamet (nabilone in Canada, Mexico, the United States and the United Kingdom).b[›]
Currently, the U.S. Food and Drug Administration (FDA) has not approved smoked cannabis for any condition or disease in the United States, largely because good quality scientific evidence for its use from U.S. studies is lacking. Regardless, fourteen states have legalized cannabis for medical use. The United States Supreme Court has ruled in United States v. Oakland Cannabis Buyers’ Coop and Gonzales v. Raich that it is the federal government that has the right to regulate and criminalize cannabis, even for medical purposes. Canada, Spain, The Netherlands and Austria have legalized some form of cannabis for medicinal use
Dried Cannabis flowers in natural herbal form
The terms cannabis or marijuana generally refer to the dried flowers and subtending leaves and stems of the female cannabis plant. This is the most widely consumed form, containing 3% to 22% THC. In contrast, cannabis varieties used to produce industrial hemp contain less than 1% THC and are thus not valued for recreational use.
Kief is a powder, rich in trichomes, which can be sifted from the leaves and flowers of cannabis plants and either consumed in powder form or compressed to produce cakes of hashish.
Hashish (also spelled hasheesh, hashisha, or simply hash) is a concentrated resin produced from the flowers of the female cannabis plant. Hash can often be more potent than marijuana and can be smoked or chewed. It varies in color from black to golden brown depending upon purity.
Hash oil, or “butane honey oil” (BHO), is a mix of essential oils and resins extracted from mature cannabis foliage through the use of various solvents. It has a high proportion of cannabinoids (ranging from 40 to 90%). and is used in a variety of cannabis foods.
Because of THC’s adhesive properties, a sticky residue, most commonly known as “resin”, builds up inside utensils used to smoke cannabis. It has tar-like properties but still contains THC as well as other cannabinoids. This buildup retains some of the psychoactive properties of cannabis but is more difficult to smoke without discomfort caused to the throat and lungs. This tar may also contain CBN, which is a breakdown product of THC. Cannabis users typically only smoke residue when cannabis is unavailable. Glass pipes may be water-steamed at a low temperature prior to scraping in order to make the residue easier to remove.