Cannabis abuse ‘may lead’ to psychosis

The risk of developing psychosis has proven to be higher for people who abuse cannabis.

Researchers from the Norwegian Institute of Public Health (NIPH) and Virginia Commonwealth University came to this conclusion following a study carried out on Norwegian twins.

The study examined the relationship between cannabis and psychosis using psychiatric interviews of the twins.

“Previous research has shown that patients with psychotic disorders use cannabis more often than the general population.

“However research has been divided over whether cannabis use was the cause of the psychotic disorders,” says Ragnar Nesvåg, senior researcher at NIPH and the main author of the study.

Genetic factors influence both cannabis abuse and psychosis and the same genes may lead to an increased risk for both problems.

“The relative importance of genes in the causes of a disease is known as heritability, and we know from previous studies at the NIPH that cannabis abuse is very heritable” explains Eivind Ystrom, senior researcher at NIPH.

“In order to determine whether cannabis abuse can lead to psychosis, it is important to account for genetic risk,” he added.

Studies have also shown that cannabis abuse can be passed through genes from generation to generation which was also made apparent in the study.