Preliminary study: Heavy cannabis users have trouble letting go of bad memories

Chronic marijuana users have trouble letting go of negative emotions or bad memories, a new preliminary study from Ontario’s University of Windsor shows.

The study, presented on Friday at the annual meeting of the Association for Psychological Science, could link chronic marijuana use with depression, Live Science reported.

It explored what is known as the “fading affect bias,” where people hold on their positive emotions far more on their negative feelings, or people evict their bad memories far more than their positive ones.

The “fading affect bias” is by far seen with people, who are considerably far more mentally healthy and could serve as some type of “Psychological immune system,” Daniel Pillersdorf, the lead author of the study, said.

Psychologically, clinging to bad memories is a phenomenon seen in people who have depression.

In the study, 46 chronic marijuana users, who consumed cannabis at least four times a week, were compared to 51 others, who don’t use weed at all.

They were asked to recall, and provide written descriptions of, three pleasant memories and three unpleasant memories from the past year.  They were later asked to rate their memories on a scale of 10 if they were extremely unpleasant and again on a scale of 10 if they were extremely pleasant.

They rated their emotions both at the time the memory was made and at the current time. Also, marijuana users were not under the influence at the time the researchers asked them the questions.

The researchers found that both marijuana users and nonusers showed “fading affect bias,” but for marijuana users, the fading was a lot less.

“They were hanging on to that unpleasant affect over time, much more” than nonusers, Pillersdorf, who is a graduate student at the University of Windsor, told Live Science.

“They were less able … to shed that unpleasantness associated with their memories.”

The preliminary research also showed that marijuana users recalled life in a more general term as opposed to being specific such as “I went on vacation,” and not giving extra illuminating details.

This phenomenon is known as “overgeneral autobiographical memory,” and it’s also linked with depression, Pillersdorf added.

So far, the study only reveals an association and doesn’t prove causality.