Navigation Links
Cannabis linked to earlier onset of psychosis

A new study has provided the first conclusive evidence that cannabis use significantly hastens the onset of psychotic illnesses during the critical years of brain development with possible life-long consequences.

The first ever meta-analysis of more than 20,000 patients shows that smoking cannabis is associated with an earlier onset of psychotic illness by up to 2.7 years.

The analysis, by an international team including Dr Matthew Large, from the University of New South Wales (UNSW) School of Psychiatry and Sydney's Prince of Wales Hospital, is published today in the prestigious journal Archives of General Psychiatry.

In partnership with St Vincent's Hospital and The George Washington University School of Medicine and Health Sciences, the study set out to establish the extent to which use of cannabis, alcohol and other psychoactive substances affects the age at onset of psychotic illnesses such as schizophrenia.

Cannabis is the most widely used illicit drug in Australia with 33.5% of the population reporting use at some time, according to the 2007 National Drug Household Survey. Some 18% of all secondary school students aged 12-17 reported using the drug at some time in their life, according to the 2004 Secondary School Survey. (UNSW's National Cannabis Prevention and Information Centre

Building on several decades of research, the finding is an important breakthrough in the understanding of the relationship between cannabis use and psychosis, Dr Large said.

A number of previous studies have found an association between psychosis and the use of cannabis, alcohol and other psychoactive substances. However, the aim of this study was to specifically show the extent to which this is caused by cannabis use alone, he said.

The current findings support the view that cannabis use precipitates schizophrenia and other psychotic disorders, perhaps through an interaction between genetic and environmental disorders or by disrupting brain development, the team notes.

"The study re-analysed the results from 20,000 patients with schizophrenia or other psychotic illnesses from 83 previous studies. The study used meta-analysis a modern statistical method to show that an earlier onset of severe mental illness among substance users is a result of cannabis use, and cannot be explained by other factors such as alcohol use," Dr Large said.

"Results of this study are conclusive and clarify previously conflicting evidence of a relationship between cannabis use and the earlier onset of a psychotic illness, with evidence supporting the theory that cannabis use plays a causal role in the development of psychosis in some patients."

Dr Large said there was a high prevalence of substance use among individuals treated in mental health settings, and patients with schizophrenia were more likely to use substances than members of the wider community.

"The results of this study provide strong evidence that stopping or reducing cannabis use could delay or even prevent some cases of psychosis.

"The study raises the question of whether those substance users would still have gone on to develop psychosis a few years later.

"However, even if the onset of psychosis were inevitable, an extra two or three years of psychosis-free functioning could allow many patients to achieve important developmental milestones of late adolescence and early adulthood that could lower long-term disability arising from psychotic disorders," Dr Large said.

"The results of this study confirm the need for an ongoing public health warning about the potentially harmful effects of cannabis."


Contact: Steve Offner
University of New South Wales

Related biology news :

1. Daily consumption of cannabis predisposes to the appearance of psychosis and schizophrenia
2. Weeding out marijuana: Researchers close in on engineering recognizable, drug-free Cannabis plant
3. Breast cancer treatment resistance linked to signaling pathway
4. Lack of vitamin D linked to Parkinsons disease
5. Resveratrol, red wine compound linked to health, also found in dark chocolate and cocoa
6. Racial disparities in cardiovascular health linked to birth weight, slavery
7. Geologist who linked cosmic strike to dinosaurs extinction takes top prize
8. Hypertension disparity linked to environment
9. Seasonal affective disorder may be linked to genetic mutation, study suggests
10. Shifts in soil bacterial populations linked to wetland restoration success
11. Hairspray is linked to common genital birth defect, says study
Post Your Comments:
(Date:11/12/2015)... , Nov. 12, 2015  A golden retriever ... Duchenne muscular dystrophy (DMD) has provided a new lead ... Children,s Hospital, the Broad Institute of MIT and Harvard ... Brazil . Cell, pinpoints ... dogs "escape" the disease,s effects. The Boston Children,s lab ...
(Date:11/10/2015)... 2015  In this report, the biomarkers ... product, type, application, disease indication, and geography. ... are consumables, services, software. The type segments ... efficacy biomarkers, and validation biomarkers. The applications ... development, drug discovery and development, personalized medicine, ...
(Date:11/4/2015)... --> --> ... Transparency Market Research "Home Security Solutions Market - Global Industry ... 2022", the global home security solutions market is expected to reach ... market is estimated to expand at a CAGR of ... Rising security needs among customers at homes, the emergence ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... 24, 2015  Asia-Pacific (APAC) holds the third-largest ... market. The trend of outsourcing to low-cost locations ... higher volume share for the region in the ... margins in the CRO industry will improve. ... ( ), finds that the market earned ...
(Date:11/24/2015)... ... 24, 2015 , ... Copper is an essential micronutrient that ... proteins, copper is also toxic to cells. With a $1.3 million award from ... conduct a systematic study of copper in the bacteria Pseudomonas aeruginosa (P. aeruginosa), ...
(Date:11/24/2015)... ... 24, 2015 , ... This fall, global software solutions leader SAP and AdVenture ... develop and pitch their BIG ideas to improve health and wellness in their schools. ... to win the title of SAP's Teen Innovator, an all-expenses paid trip to Super ...
(Date:11/24/2015)... , Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris ... today that the remaining 11,000 post-share consolidation (or ... Warrants (the "Series B Warrants") subject to the ... on November 23, 2015, which will result in ... giving effect to the issuance of such shares, ...
Breaking Biology Technology: