Cannabis use disorder in the DSM-V involves a combination of DSM-IV criteria for cannabis abuse and dependence, plus the addition of craving, without the criterion related to legal troubles. Psychiatric
At an epidemiological level, a dose–response relationship exists between cannabis use and increased risk of psychosis and earlier onset of psychosis. Although the epidemiological association is robust, evidence to prove a causal relationship is lacking. But a biological causal pathway is plausible, especially if there is a genetic predisposition to mental illness, in which case cannabis may be a trigger.Cannabis may also increase the risk of depression, but insufficient research has been performed to draw a conclusion. Cannabis use is associated with increased risk of anxiety disorders, although causality has not been established.A review in 2019 found that research was insufficient to determine the safety and efficacy of using cannabis to treat schizophrenia, psychosis, or other mental disorders. Another found that cannabis during adolescence was associated with an increased risk of developing depression and suicidal behavior later in life, while finding no effect on anxiety. Physical
Heavy, long-term exposure to marijuana may have physical, mental, behavioral and social health consequences. It may be "associated with diseases of the liver (particularly with co-existing hepatitis C), lungs, heart, and vasculature". A 2014 review found that while cannabis use may be less harmful than alcohol use, the recommendation to substitute it for problematic drinking was premature without further study.
: p104  Aside from a subjective change in perception and mood, the most common short-term physical and neurological effects include increased heart rate, increased appetite, impairment of short-term and working memory, and psychomotor coordination.Additional desired effects from consuming cannabis include relaxation, a general alteration of conscious perception, increased awareness of sensation, increased libido and distortions in the perception of time and space. At higher doses, effects can include altered body image, auditory and/or visual illusions, pseudohallucinations and ataxia from selective impairment of polysynaptic reflexes. In some cases, cannabis can lead to dissociative states such as depersonalization and derealization. Spiritual
Cannabis has held sacred status in several religions and has served as an entheogen – a chemical substance used in religious, shamanic, or spiritual contexts – in the Indian subcontinent since the Vedic period. The earliest known reports regarding the sacred status of cannabis in the Indian subcontinent come from the Atharva Veda, estimated to have been composed sometime around 1400 BCE. The Hindu god Shiva is described as a cannabis user, known as the "Lord of bhang. : p19 In modern culture, the spiritual use of cannabis has been spread by the disciples of the Rastafari movement who use cannabis as a sacrament and as an aid to meditation. Modes of cannabis consumption
Cannabis is consumed in many different ways, all of which involve heating to decarboxylate THCA in the plant into THC.