A new study has concluded that the number of schizophrenia cases being linked to cannabis use disorder has grown significantly over the last 25 years.
CNN reports that Danish researchers found that, while in 1995 only 2% of schizophrenia diagnoses in the country were associated with cannabis use disorder, by 2000 this had increased to 4%, seeing another increase to 8% by 2010.
Carsten Hjorthøj, an associate professor at the Copenhagen Research Center for Mental Health and an author of the study published in the medical journal JAMA Psychiatry, told CNN: “I think it is highly important to use both our study and other studies to highlight and emphasise that cannabis use is not harmless.
“There is, unfortunately, evidence to suggest that cannabis is increasingly seen as a somewhat harmless substance. This is unfortunate since we see links with schizophrenia, poorer cognitive function, substance use disorders, etc.”
“Of course, our findings will have to be replicated elsewhere before firm conclusions can be drawn. But I do feel fairly confident that we will see similar patterns in places where problematic use of cannabis has increased, or where the potency of cannabis has increased since many studies suggest that high-potency cannabis is probably the driver of the association with schizophrenia.”
Cannabis has long been very popular worldwide. In fact, cannabis is reported to be the most commonly used substance of abuse after alcohol and tobacco in the US. In 2015, researchers found that four million people in the US were struggling with cannabis use disorder.
While it is commonly believed that around 10% of cannabis users will form an addiction to the substance, some estimates suggest that almost a third of those who use cannabis may have some degree of cannabis use disorder.
Another study concluded that cannabis withdrawal symptoms “resemble” other drugs, such as tobacco; however, these symptoms are considered to be mild compared to other drugs as they don’t include any major medical or psychiatric consequences.
Heavy-users often report numerous issues, such as mood and sleep difficulties, decreased appetite, cravings and restlessness, which usually peak within the first week after quitting and last up to two weeks.
Marvin D. Seppala, MD, Chief Medical Officer, Hazelden Betty Ford Foundation, reiterated that limitless cannabis use can lead to addiction.
He said: “Most people can use marijuana without becoming addicted, and most who use occasionally will not suffer harmful effects.
“Still, it is important to know the risks, especially considering the new forms and tremendously high levels of THC available to users.
“The higher the potency of the drug consumed, the higher the likelihood of addiction, and the higher the likelihood of adverse side effects.
“It is also important to recognize that marijuana has several hundred ingredients, many of which we know very little about. With new research, more information will be coming to help us understand both the good and bad effects of marijuana in all of its forms.”