A provocative new study by Norwegian researchers suggests cannabis use causes a temporary cognitive breakdown in non-psychotic individuals.
Investigators believe this alteration in brain activity can lead to long-term psychosis.
In the study, researchers found a different brain activity pattern in schizophrenia patients with previous cannabis use than in schizophrenic patients without prior cannabis use.
The results reinforce the researcherâ€™s belief that cannabis users suffering from schizophrenia actually may have higher cognitive abilities than non-cannabis-using schizophrenics.
This difference may indicate that the cannabis-user group did not have the same mental propensity for psychosis.
“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.
“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,” said Else-Marie Loeberg, Ph.D., of the University of Bergen, the lead author on the article.
Researchers studied 26 patients asking them to attempt difficult cognitive tasks while in the fMRI machine.
Participants were asked to listen to different syllables in each ear and try to say which syllable was spoken when instructed to concentrate on either the left or right earâ€”a difficult task for anyone.
The task is especially difficult for schizophrenia patients who often have impaired attention, limited executive functioning and difficulty in processing verbal cues.
Researchers discovered that schizophrenia sufferers with previous cannabis use had consistently higher levels of brain activity while undergoing these tests as well as a higher number of correct answers.
These results are congruent with previous earlier findings by the researchers that cannabis users with schizophrenic characteristics do not appear to suffer from the same neurocognitive weaknesses as other patients with schizophrenia.
This premise could imply that cannabis use leads otherwise non-psychotic individuals to potential psychosis by imitating the cognitive weakness that is a risk factor for developing the psychological condition.
Study findings are published in the journal Frontiers in Psychiatry.