Cannabis Consumption Can Cause False Memory Formation, Finds New Study


Cannabis may come with health benefits, but the plant has several negative side effects of use. Now with gaining the legal status, concerns over its use are rising. Past studies show that cannabis can affect cognition.

It can affect your learning, attention, and memory adversely. With cannabis use, you are likely to find yourself distracted, and disoriented. It can also affect your balance and coordination.

Now new study shows that the THC in cannabis can cause people to form false memories. This is a significant issue from the legal point of view as well. Researchers wanted to look at the effects of cannabis on memory formation as previous research already shows that acute or chronic cannabis use can impair verbal memory.

Legally this is of importance because eyewitnesses who have taken cannabis cannot be relied on because their memories can be false. This means either they have memories of events that did not take place or they have altered past memories.

Diving Into The Research Work

For the purpose of this study, the team of researchers looked at the effects of THC intoxication on 64 otherwise healthy volunteers. They wanted to look at how THC caused false memories. The study was a double-blind randomized control trial.

Results of participants who had used cannabis were compared to those who received placebo instead. Participants’ memories were tested immediately after THC consumption and following a week of use. For testing the memory of participants, researchers used associative word lists as well as two misinformation activities.

As part of the first tests, all volunteer participants looked at 15 lists of related words. Interestingly, people who had taken THC said that they recognized words that they hadn’t been shown previously. In the second part of the study, researchers used virtual reality to make participants experience two scenes.

The first was a fight scene at a train station in which participants were eyewitnesses and the second was handbag theft at a bar in which they were perpetrators. After viewing these scenes, participants answered questions regarding what had happened. To note whether intoxicated individuals are reliable, researchers asked inaccurate questions as well.

What Did Researchers Find?

Findings revealed the THC group reported false memories more than the placebo group. The THC group was not only susceptible to false memory formation immediately after the test. In fact, when scientists repeated the experiments following a week of intoxication, when participants were sober, they were still susceptible to false memory formation.

This means that police cannot rely on the testimony or answers of witnesses, victims, and suspects when they are under cannabis intoxication. Their interviews should wait until they are sober enough to answer questions correctly.

Final author of the study, Prof. Johannes Ramaekers said, “People under the influence of cannabis should actually be treated as a vulnerable group in a criminal investigation, comparable with children and the elderly.The Proceedings of the National Academy of Sciences journal published this research work.


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