Cannabis increases brain inflammation in psychotic episodes, according to a study

Barcelona.- People who suffer a first psychotic episode and consume cannabis present more brain inflammation than those who suffer from the same disorder but do not take this substance, according to a study. According to this research, led by a team from the Hospital del Mar Research Institute of Barcelona (northeast of Spain) and published by the journal Molecular Psychiatry, this effect is the opposite of what happens in the case of people without psychotic episodes. This fact may explain the lower therapeutic capacity of the treatments used in this disorder in people who consume cannabis, indicates the study, which was reported on Thursday by the Hospital del Mar. Cannabis use is one of the most well-documented risk factors for psychosis, as well as one of the elements that can influence the onset of the disorder.

It is estimated that between 30 and 50% of people who experience a first psychotic episode are users of this substance.

The study has used for the first time a new technique that measures extracellular free water, a marker of inflammation, in brain images obtained with diffusion magnetic resonance imaging to demonstrate an association between cannabis use and brain inflammation, one of the least known factors in psychosis.

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In the research, 62 patients recently diagnosed with psychotic disorders and 38 controls participated. The work results show differences in brain inflammation between people suffering a first psychotic episode depending on whether they consume cannabis or not. The results obtained indicate that cannabis may influence the ability of psychosis treatments to reduce this inflammation, the researchers point out. According to Laura Martínez Sadurní, author of the work and psychiatrist at Hospital del Mar, in daily practice it is already conveyed to patients that cannabis consumption can influence the fact that they have more psychotic symptoms and that the evolution is worse. But now the conclusions of the new study add new evidence: "The fact of knowing that cannabis interferes with the positive effect of antipsychotics allows us to give more forceful indications that its consumption is contraindicated after a first psychotic episode", he specifies.