Nav: Home

Marijuana may produce psychotic-like effects in high-risk individuals

September 13, 2017

New York, NY (Sept. 13, 2017) - Marijuana may bring on temporary paranoia and other psychosis-related effects in individuals at high risk of developing a psychotic disorder, finds a preliminary study from researchers at Columbia University Medical Center (CUMC).

The study was published last month in an online edition of Psychiatry Research.

Individuals who have had mild or transient psychotic symptoms (such as unusual thoughts, suspiciousness, perceptual disturbances) without using substances such as marijuana or alcohol and have a family history of psychosis or other risk factors are considered at clinical high risk for psychotic disorder. Previous studies have found an association between marijuana use and psychosis in the general population, but none have rigorously examined marijuana's effects in those at greatest risk for psychosis.

"Many adolescents and young adults who are at high risk for psychosis smoke marijuana regularly or have a cannabis use disorder," said Margaret Haney, PhD, professor of neurobiology (in Psychiatry) at CUMC and senior author of the paper. "Yet researchers haven't studied the effects of marijuana in this population in a rigorous, controlled manner."

In this double-blinded, placebo-controlled laboratory study, the researchers looked at the effects of marijuana in six high-risk young adults and six controls, all experienced and current marijuana smokers who were physically healthy. Participants smoked half of an active or placebo marijuana cigarette, had psychological and physiological assessments before and after smoking, and then repeated this procedure with the opposite (active or placebo) cigarette.

After smoking active marijuana, both groups had signs of intoxication and increases in heart rate and arousal relative to the placebo. However, only the high-risk group experienced transient increases in paranoia and anxiety, as well as disrupted sensory perception and cognitive performance, after using active marijuana. Neither group experienced these effects after using the placebo.

"Although this was a small, preliminary study, it suggests that marijuana may affect individuals at high risk for psychosis differently than other marijuana users, by briefly inducing psychotic-like experiences and impairing their cognition," said Nehal Vadhan, PhD, a psychologist and associate professor in Psychiatry and Molecular Medicine at Hofstra Northwell School of Medicine and first author of the paper. "While larger studies are needed to confirm these findings, they may aid clinicians in their guidance to individuals at risk for psychosis about marijuana's potential effects."

Jeffrey Lieberman,MD, chair of psychiatry at CUMC and and former American Psychiatric Association president, noted that this report "demonstrates the convergent risks of adolescence and expanding cannabis use for the development of psychotic disorders, as well as the opportunity for preventive strategies."

-end-

The study is titled, "Acute effects of smoked marijuana in marijuana smokers at clinical high-risk for psychosis: A preliminary study." Authors are Nehal Vadhan (Hofstra Northwell School of Medicine and the Feinstein Institute for Medical Research, Hempstead and Manhasset, NY), Cheryl Corcoran (CUMC, Icahn School of Medicine at Mount Sinai, New York, NY), Gill Bedi (University of Melbourne & Orygen National Centre of Excellence in Youth Mental Health Melbourne, Australia), John Keilp (CUMC and New York State Psychiatric Institute (NYSPI)), and Margaret Haney (CUMC and NYSPI).

Funding for the study was provided by a Brain and Behavior Research Foundation Young Investigator Award, the National Institutes of Health (DA19239, MH086125), and CUMC Irving Scholar Awards.

The authors report no financial or other conflicts of interest.

Columbia University Medical Center provides international leadership in basic, preclinical, and clinical research; medical and health sciences education; and patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, public health professionals, dentists, and nurses at the College of Physicians and Surgeons, the Mailman School of Public Health, the College of Dental Medicine, the School of Nursing, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. Columbia University Medical Center is home to the largest medical research enterprise in New York City and State and one of the largest faculty medical practices in the Northeast. The campus that Columbia University Medical Center shares with its hospital partner, New York-Presbyterian, is now called the Columbia University Irving Medical Center. For more information, visit cumc.columbia.edu or columbiadoctors.org.

Columbia University Department of Psychiatry

Columbia Psychiatry is among the top ranked psychiatry departments in the nation and has contributed greatly to the understanding and treatment of brain disorders. Co-located at the New York State Psychiatric Institute on the New York-Presbyterian Hospital/Columbia University Medical Center campus in Washington Heights, the department enjoys a rich and productive collaborative relationship with physicians in various disciplines at Columbia University's College of Physicians and Surgeons. Columbia Psychiatry is home to distinguished clinicians and researchers noted for their clinical and research advances in the diagnosis and treatment of depression, suicide, schizophrenia, bipolar and anxiety disorders, eating disorders, substance use disorders, and childhood psychiatric disorders.

Columbia University Medical Center

Related Marijuana Articles:

Why the marijuana and tobacco policy camps are on very different paths
Paper looks at diverging trajectories of cannabis and tobacco policies in the US and attempts to explain some of the reasoning behind the different paths, while discussing possible implications.
Legalizing marijuana will harm health of youth in Canada
The federal government's bill C-45 to legalize marijuana in Canada will jeopardize the health of young people and Parliament should vote against it, argues the interim editor-in-chief of CMAJ in an editorial.
Study: Trying new marijuana products and edibles is associated with unexpected highs
A new study by RTI International suggests that unexpected highs are a consequence of using new marijuana products and edibles--products that have flooded the marijuana market since legalization of recreational marijuana use.
Marijuana use tied to poorer school performance
When high school students started smoking marijuana regularly they were less likely to get good grades and want to pursue university, according to a new study from the University of Waterloo.
Chili peppers and marijuana calm the gut
You wouldn't think chili peppers and marijuana have much in common.
Depression, alcohol, and marijuana linked to later use of synthetic marijuana among teens
In the first prospective study of synthetic cannabinoids or SCs -- the group of chemicals that mimic the effects of marijuana -- researchers have found that symptoms of depression, drinking alcohol, or using marijuana was linked to an increased risk of SC use one year later.
Consumption of alcohol and marijuana associated with lower GPA in college
College students who consume medium-to-high levels of alcohol and marijuana have a consistently lower GPA, according to a study published March 8, 2017 in the open-access journal PLOS ONE by Shashwath Meda from Hartford Hospital/Institute of Living, USA, and colleagues.
How can marijuana policy protect the adolescent brain?
As more states begin to legalize the use of marijuana, more young people may believe that it's safe to experiment with the drug.
Shift in some teens' use and perceptions of marijuana after recreational marijuana is legalized
Marijuana use significantly increased and its perceived harm decreased among eighth- and 10th-graders in Washington state following enactment of recreational marijuana laws, according to a UC Davis and Columbia University study.
Did teen perception, use of marijuana change after recreational use legalized?
Marijuana use increased and the drug's perceived harmfulness decreased among eighth- and 10th-graders in Washington after marijuana was legalized for recreational use by adults but there was no change among 12th-graders or among students in the three grades in Colorado after legalization for adults there, according to a new study published online by JAMA Pediatrics.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: Radiolab

Oliver Sipple
One morning, Oliver Sipple went out for a walk. A couple hours later, to his own surprise, he saved the life of the President of the United States. But in the days that followed, Sipple's split-second act of heroism turned into a rationale for making his personal life into political opportunity. What happens next makes us wonder what a moment, or a movement, or a whole society can demand of one person. And how much is too much?
Now Playing: TED Radio Hour

Future Consequences
From data collection to gene editing to AI, what we once considered science fiction is now becoming reality. This hour, TED speakers explore the future consequences of our present actions. Guests include designer Anab Jain, futurist Juan Enriquez, biologist Paul Knoepfler, and neuroscientist and philosopher Sam Harris.