Cannabis could increase risk of psychotic illness later in life by over 40 percent

July 26, 2007

There is now enough evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life by more than 40%, conclude authors of an Article published in this week's edition of The Lancet. The issues are also explored in an accompanying Comment and Editorial, with the Editorial concluding: "Governments would do well to invest in sustained and effective education campaigns on the risks to health of taking cannabis."

Cannabis, or marijuana, is the most commonly used illegal substance in most countries, including the UK and USA. Up to 20% of young people now report use at least once per week or heavy use (use on more than 100 occasions).

Dr Theresa Moore, University of Bristol, and Dr Stanley Zammit, Cardiff University, Wales, and colleagues did a meta-analysis of 35 studies, dated up to 2006, to assess whether there was evidence to connect cannabis use to occurrence of psychotic or mental health disorders.

They found that individuals had used cannabis ever were 41% more likely than those who had never used the drug to have any psychosis. The risk increased relative to dose, with the most frequent cannabis users more than twice as likely to have a psychotic outcome. Depression, suicidal thoughts, and anxiety outcomes were examined separately, and findings for these outcomes were less consistent, with fewer attempts made to address non-causal explanations than for psychosis.

The authors say that recent estimates of the proportion of young adults and adolescents who have ever used cannabis is 40%. If having ever used cannabis increases the risk of a psychotic outcome by 41%, about 14% of psychotic outcomes in young adults in the UK would not occur in cannabis were not consumed.

The authors say: "We have described a consistent association between cannabis use and psychotic symptoms, including disabling psychotic disorders."

They conclude: "Despite the inevitable uncertainty, policymakers need to provide the public with advice about this widely used drug. We believe that there is now enough evidence to inform people that using cannabis could increase their risk of developing a psychotic illness later in life."

In the accompanying Comment, Drs Merete Nordentoft and Carsten Hjorthaj, Copenhagen University Hospital, Denmark say: "In the public debate, cannabis has been considered a more or less harmless drug compared with alcohol, central stimulants, and opioids. However, the potential long-term hazardous effects of cannabis with regard to psychosis seem to have been overlooked, and there is a need to warn the public of these dangers, as well as to establish a treatment to help young frequent cannabis users."
-end-


Lancet

Related Cannabis Articles from Brightsurf:

Cannabis to treat gynecological conditions
A significant number of women would consider using cannabis to treat gynecological conditions, primarily gynecological pain.

Cannabis data lacking, but machine learning could help
Everyone's heard of THC and CBD. But many other active compounds in cannabis interact to influence its effects.

Cannabis use for menopause symptom management
CLEVELAND, Ohio (September 28, 2020)--As legislation relaxes regarding cannabis, it is being used to manage numerous chronic health conditions and mood symptoms.

Prescribed CBD could help people quit cannabis
A benchmark clinical trial published today shows that cannabidiol (CBD) could be a safe and effective treatment for problematic cannabis use.

Pregnant women with depression are more than 3 times more likely to use cannabis
Cannabis use is much more common among pregnant women with depression and pregnant women with depression are more than 3 times more likely to use cannabis than those without depression.

Cannabis compound acts as an antibiotic 
Public health agencies worldwide have identified antibiotic resistance of disease-causing bacteria as one of humanity's most critical challenges.

Cannabis use during pregnancy
The large health care system Kaiser Permanente Northern California provides universal screening for prenatal cannabis use in women during pregnancy by self-report and urine toxicology testing.

Questions and answers about cannabis use during pregnancy
A new study shows that women have many medical questions about the use of cannabis both before and during pregnancy, and during the postpartum period while breastfeeding.

Managing cannabis use in breastfeeding women
As more states legalize medicinal and recreational cannabis use and increasingly decriminalize cannabis, the risk to the growth and development of breastfeeding infants whose mothers use cannabis becomes a growing public health concern.

Cannabis edibles present novel health risks
With the recent legalization of cannabis edibles in Canada, physicians and the public must be aware of the novel risks of cannabis edibles, argue authors in a commentary in CMAJ (Canadian Medical Association Journal).

Read More: Cannabis News and Cannabis Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.