A recent study published in Schizophrenia Bulletin suggests that daily use of high-potency cannabis can lead to chronic users experiencing their first psychotic episode earlier than they otherwise would. A team of researchers led by Dr. Maria Di Forti at the Institute of Psychiatry at King's College in London surveyed 410 patients between the ages of 18 and 65, all of whom had a history of psychotic episodes. The survey examined history of drug, alcohol, and tobacco use as well as the age at which the patients first experienced a psychotic episode.
What the researchers found was that males were more likely to use cannabis overall than females and also experienced psychosis at a younger age. They also found that patients who started smoking cannabis at age 15 or younger preferred to smoke high-potency "skunk" cannabis rather than lower potency "hash" type cannabis. The earliest onset of psychotic episodes occurred in males who have been smoking high-potency cannabis on a daily basis -- on average, their first psychotic episode occurred six years earlier than for non-users.
Skunk cannabis has become increasingly popular in recent years with a THC content of 16 percent compared to the 4 per cent found in lower-potency "hash-type" cannabis. Though news reports have raised concerns about the dangers associated with skunk cannabis, including people being admitted to hospitals for mental health problems, skeptics have disputed the potential risks involved. Believed to have originated in the United States, European growers have developed a profitable business growing skunk cannabis in hothouses. Users often regard it as being safer than than regular marijuana because it is harder to fake but long-term use of skunk cannabis has been linked to adverse psychiatric effects including depression.
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