THC (Tetrahydrocannabinol) – is the main psychoactive cannabinoid of cannabis. It is the most well known of the cannabinoids. THC levels varies between strains but the effects are common throughout all strains.
THC effects include but are not limited to: relaxation, alteration of visual, auditory and olfactory senses. Is known to cause fatigue and appetite stimulation. It may also reduce aggression during use and increase aggression during withdrawal.
Its status as an illegal drug in most countries can make research difficult; for instance in the United States where the National Institute on Drug Abuse was the only legal source of cannabis for researchers until it recently became legalized in Colorado, Washington state, Oregon, Alaska, and Washington D.C.
The impact of the effects of THC may be greater in novice users. Studies of long-term effects on cognition have provided conflicting results, with some studies finding no difference between long-term abstainers and never-users and others finding long-term deficits.