Recent quotes:

Age-dependent association of cannabis use with risk of psychotic disorder | Psychological Medicine | Cambridge Core

Compared to no cannabis use, cannabis use was significantly associated with psychotic disorders during adolescence (aHR = 11.2; 95% CI 4.6–27.3), but not during young adulthood (aHR = 1.3; 95% CI 0.6–2.6). When we restricted the outcome to hospitalizations and ED visits only, the strength of association increased markedly during adolescence (aHR = 26.7; 95% CI 7.7–92.8) but did not change meaningfully during young adulthood (aHR = 1.8; 95% CI 0.6–5.4).

Pot withdrawal eased for dependent users | YaleNews

Withdrawal symptoms are marked by craving for marijuana, irritability, anger, depression, insomnia, and decrease in appetite and weight. In 2015, about 4 million people in the United States met the diagnostic criteria for a cannabis use disorder, and almost 150,000 voluntarily sought treatment for their cannabis use. According to recent national data, approximately one-third of all current cannabis users meet diagnostic criteria for CUD.

Running } endocannabinoids } dopamine } motivation?

The researchers also examined the role that endocannabinoids play in this process. Endocannabinoids, brain chemicals that resemble the active ingredients in marijuana, play key roles in many brain processes. Here, Dr. Cheer and his colleagues found that endocannabinoids essentially open the gate that allows the dopamine neurons to fire. When the researchers reduced the level of endocannabinoids, the animals were much less likely to move to avoid shocks.

In test with rats, cannabidiol showed sustained effects against depression for seven days -- ScienceDaily

"The forced swim test is used to measure the effect of antidepressant drugs because all known antidepressants shorten the duration of immobility and hence lengthen swim time. A reduction in immobility time in this test is interpreted as 'antidepressant-like' behavior." The researchers found that cannabidiol induced acute and sustained antidepressant-like effects in mice submitted to the forced swim test. "However, to make sure this result isn't due to the increase in movement caused by a psychostimulant effect leading the animals to swim more vigorously, for example, we performed a separate test to control for locomotor activity," Joca explained. "To do this we used the open-field test, which consists of putting the animal in a novel arena and letting it explore the new environment freely while its locomotor and exploratory activity is recorded. A drug is said to have potential antidepressant effects if it reduces immobility time and increases swim time in the forced swim test without increasing locomotor activity in the open-field test, showing that the effects observed in the forced swim test aren't secondary to nonspecific alterations in locomotor activity."

Male tobacco smokers have brain-wide reduction of CB1 receptors: A study examines cannabinoid CB1 receptor binding in healthy male tobacco smokers -- ScienceDaily

The study, the result of a collaboration of researchers affiliated with the National Institutes of Health, Maryland, supports that CB1 receptors play a role in smoking. The findings add to the group's previous studies that report the same finding in people who abuse cannabis or alcohol, suggesting that reduction of CB1 receptors is a common feature of addiction. Of the 46 men who participated in the study all were considered healthy -- 18 of the participants were frequent cigarette smokers and 28 did not smoke. The researchers measured the number of receptors by using a brain imaging technique to detect a drug that binds to CB1 receptors. The analysis indicated a nearly 20 percent reduction in CB1 receptors in the brains of smokers compared to non-smokers. The reduced receptor number was present throughout the brain (in all 18 regions examined in the study), with some regions more affected than others. The reduction in receptors was not exacerbated by more cigarettes smoked per day, or by starting before the age of 18.

Cannabis link to relieving intestinal inflammation explained -- ScienceDaily

The researchers discovered that gut inflammation is regulated by two important processes, which are constantly in flux and responding to changing conditions in the intestinal environment. The first process, identified in previous scientific research, promotes an aggressive immune response in the gut that destroys dangerous pathogens, but which can also damage the lining of the intestine when immune cells attack indiscriminately. The second pathway, first described in this paper, turns off the inflammation response via special molecules transported across the epithelial cells lining the gut by the same process already known to remove toxins from these cells into the intestine cavity. Crucially, this response requires a naturally-produced molecule called an endocannabinoid, which is very similar to cannabinoid molecules found in cannabis. If the endocannabinoid isn't present, inflammation isn't kept in balance and it can run unchecked, as the body's immune cells attack the intestinal lining.