Researchers in Norway claim they have found new evidence to support their theory that cannabis use causes temporary 'cognitive breakdown' in non-psychotic people, risking long-term psychosis.
According to an fMRI study published in the Frontiers in Psychiatry journal, scientists at the University of Bergen believe cannabis use raises the chances of users suffering from schizophrenic symptoms later in life.
The researchers tested 26 schizophrenics, some with a history of cannabis use, and tested their ability to listen and repeat certain syllables.
The study's results showed that schizophrenia sufferers with previous cannabis use had consistently higher levels of brain activity while undergoing these tests, and also scored a higher number of correct answers.
These results are in line with previous conclusions from the Bergen researchers who support the idea that cannabis users with schizophrenic characteristics do not appear to suffer from the same neuro-cognitive weaknesses as other patients with schizophrenia.
"While brain activity for both groups was similar, there are subtle differences between schizophrenia sufferers with a history of cannabis use and those who have never used cannabis," Else-Marie Loeberg, lead author on the article and associate professor of Psychology at the University of Bergen, Norway.
"These differences lead us to believe that the cognitive weakness leading to schizophrenia is imitated by the effects of cannabis in otherwise non-psychotic people."
The scientists believe that the study's results imply that cannabis use increases the risk of the development of psychotic symptoms, 'imitating' the cognitive weakness that is prevalent in schizophrenics.