Abstract
Abstract: Cannabis preparations are obtained from the plant Cannabis indica or sativa. Cannabis is the most widely used illicit drug in the world.
Cannabis use is illegal in most developed societies, but it has become a common feature of youth culture, with a declining age of first use among more recent birth cohorts. The active ingredient in cannabis is delta-9-tetrahydrocannabinol (THC), which binds to CB1 receptors located in the CNS.
CB1 receptors are most prominent in the basal ganglia, cerebellum, hippocampus, and neocortex. The main reason why most young people use cannabis is to experience a ""high"": mild euphoria; relaxation and perceptual alterations, including time distortion; and the intensification of ordinary experiences such as listening to music, eating, watching films, and engaging in sex.
Psychotic symptoms, such as hallucinations or delusions, are very rare experiences, that may occur at very high doses of THC and perhaps in susceptible individuals at lower doses. High doses of THC have been reported to produce visual and auditory hallucinations, delusional ideas, and thought disorder in normal volunteers.
Classification systems have a definition of cannabis dependence, which is characterized by marked distress resulting by a recurring cluster of problems related to cannabis use that reflect impaired control over cannabis use despite the harms such use may be causing. Studies in clinical and nonclinical samples of long-term cannabis users have reported withdrawal symptoms such as anxiety, insomnia, appetite disturbance, and depression.
Alterations in brain function and motor behavior have been reported in chronic cannabis users, but the results have been variable.