Cannabis consumers show greater susceptibility to false memories

http://www.eurekalert.org/pub_releases/2015-04/uadb-ccs042115.php

Public Release: 21-Apr-2015
Universitat Autonoma de Barcelona

The study conducted at Sant Pau and Bellvitge hospitals, published in the American journal Molecular Psychiatry and conducted with the use of neuroimaging techniques, demonstrates for the first time that cannabis consumers have a less active hippocampus, a key structure related to the storage of memories.

Consumers of cannabis show distortions in their memories and can even come to imagine situations which differ from reality.

The study compared the memories of consumers to that of non-consumers to find differences in the retention of situations and experiences.

The chronic use of cannabis can accentuate age-related memory problems.

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One of the known consequences of consuming this drug is the memory problems it can cause. Chronic consumers show more difficulties than the general population in retaining new information and recovering memories. The new study also reveals that the chronic use of cannabis causes distortions in memory, making it easier for imaginary or false memories to appear.

On occasions, the brain can remember things that never happened. Our memory consists of a malleable process which is created progressively and therefore is subject to distortions or even false memories. These memory "mistakes" are seen more frequently in several neurological and psychiatric disorders, but can also be observed in the healthy population, and become more common as we age. One of the most common false memories we have are of situations from our childhood which we believe to remember because the people around us have explained them to us over and over again.

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The study found memory deficiencies despite the fact that participants had stopped consuming cannabis one month before participating in the study. Although they had not consumed the drug in a month, the more the patient had used cannabis throughout their life, the lower the level of activity in the hippocampus, key to storing memories.

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