Featured Research

from universities, journals, and other organizations

Cannabis use precedes the onset of psychotic symptoms in young people, study finds

Date:
March 3, 2011
Source:
BMJ-British Medical Journal
Summary:
Cannabis use during adolescence and young adulthood increases the risk of psychotic symptoms, while continued cannabis use may increase the risk for psychotic disorder in later life, concludes a new study.

Cannabis use during adolescence and young adulthood increases the risk of psychotic symptoms, while continued cannabis use may increase the risk for psychotic disorder in later life, concludes a new study published online in the British Medical Journal.

Cannabis is the most commonly used illicit drug in the world, particularly among adolescents, and is consistently linked with an increased risk for mental illness. However, it is not clear whether the link between cannabis and psychosis is causal, or whether it is because people with psychosis use cannabis to self medicate their symptoms.

So a team of researchers, led by Professor Jim van Os from Maastricht University in the Netherlands, set out to investigate the association between cannabis use and the incidence and persistence of psychotic symptoms over 10 years.

The study took place in Germany and involved a random sample of 1,923 adolescents and young adults aged 14 to 24 years.

The researchers excluded anyone who reported cannabis use or pre-existing psychotic symptoms at the start of the study so that they could examine the relation between new (incident) cannabis use and psychotic symptoms.

The remaining participants were then assessed for cannabis use and psychotic symptoms at three time points over the study period (on average four years apart).

Incident cannabis use almost doubled the risk of later incident psychotic symptoms, even after accounting for factors such as age, sex, socioeconomic status, use of other drugs, and other psychiatric diagnoses. Furthermore, in those with cannabis use at the start of the study, continued use of cannabis over the study period increased the risk of persistent psychotic symptoms

There was no evidence for self medication effects as psychotic symptoms did not predict later cannabis use.

These results "help to clarify the temporal association between cannabis use and psychotic experiences," say the authors. "In addition, cannabis use was confirmed as an environmental risk factor impacting on the risk of persistence of psychotic experiences."

The major challenge is to deter enough young people from using cannabis so that the prevalence of psychosis is reduced, say experts from Australia in an accompanying editorial.

Professor Wayne Hall from the University of Queensland and Professor Louisa Degenhardt from the Burnet Institute in Melbourne, question the UK's decision to retain criminal penalties for cannabis use, despite evidence that removing such penalties has little or no detectable effect on rates of use. They believe that an informed cannabis policy "should be based not only on the harms caused by cannabis use, but also on the harms caused by social policies that attempt to discourage its use, such as criminal penalties for possession and use."


Story Source:

The above story is based on materials provided by BMJ-British Medical Journal. Note: Materials may be edited for content and length.


Journal References:

  1. Rebecca Kuepper, Jim van Os, Roselind Lieb, Hans-Ulrich Wittchen, Michael Hφfler, Cιcile Henquet. Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study. British Medical Journal, 2011; DOI: 10.1136/bmj.d738
  2. Wayne Hall, Louisa Degenhardt. Cannabis and the increased incidence and persistence of psychosis. BMJ, 2011; DOI: 10.1136/bmj.d719

Cite This Page:

BMJ-British Medical Journal. "Cannabis use precedes the onset of psychotic symptoms in young people, study finds." ScienceDaily. ScienceDaily, 3 March 2011. <www.sciencedaily.com/releases/2011/03/110301184056.htm>.
BMJ-British Medical Journal. (2011, March 3). Cannabis use precedes the onset of psychotic symptoms in young people, study finds. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2011/03/110301184056.htm
BMJ-British Medical Journal. "Cannabis use precedes the onset of psychotic symptoms in young people, study finds." ScienceDaily. www.sciencedaily.com/releases/2011/03/110301184056.htm (accessed August 23, 2014).

Share This




More Mind & Brain News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lost Brain Cells To Blame For Sleep Problems Among Seniors

Lost Brain Cells To Blame For Sleep Problems Among Seniors

Newsy (Aug. 21, 2014) — According to a new study, elderly people might have trouble sleeping because of the loss of a certain group of neurons in the brain. Video provided by Newsy
Powered by NewsLook.com
Do More Wedding Guests Make A Happier Marriage?

Do More Wedding Guests Make A Happier Marriage?

Newsy (Aug. 20, 2014) — A new study found couples who had at least 150 guests at their weddings were more likely to report being happy in their marriages. Video provided by Newsy
Powered by NewsLook.com
Charter Schools Alter Post-Katrina Landscape

Charter Schools Alter Post-Katrina Landscape

AP (Aug. 20, 2014) — Nine years after Hurricane Katrina, charter schools are the new reality of public education in New Orleans. The state of Louisiana took over most of the city's public schools after the killer storm in 2005. (Aug. 20) Video provided by AP
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) — Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins