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Marijuana use linked to psychosis in later life
Marijuana use linked to psychosis in later life

July 30, 2007 (Insidermedicine) Using marijuana can raise the risk of developing psychosis in later life by more than 40%, according to research published in The Lancet.

Cannabis, also known as marijuana, is the most commonly used illegal substance in most countries, including the US and UK. Up to 20% of young people now report using the substance at least once per week. 

The main active chemical in marijuana is THC, which reacts with nerve cells in the brain to create the high that users experience when they smoke marijuana. The short-term effects of marijuana can include problems with memory and learning; distorted perception; difficulty in thinking and problem solving; loss of coordination; and increased heart rate. While marijuana has been considered a fairly harmless drug compared with alcohol, central stimulants, and opioids , recent studies indicate some changes in the brain similar to those seen after long-term abuse of other major drugs.

To investigate the association between marijuana use and the occurrence of psychotic or mental health disorders, researchers analyzed 35 studies on marijuana use.

They found that smoking marijuana raised the risk of psychosis by over 40%, and the risk increased relative to the dose; the most frequent users were more than twice as likely to have a psychotic disorder. Considering that about 40% of people in the US and UK have used marijuana in their lifetime it is estimated that about 14% of psychotic disorders in young adults in these regions could be avoided if marijuana had been avoided.

Based on the potential for serious long-term effects, it will be important for policymakers to inform the public that using marijuana could increase their risk of developing a psychotic illness later in life. As well, treatments need to be established to reduce the risk of mental health problems for young frequent marijuana users.

Reporting for Insidermedicine, I’m Dr. Susan Sharma.