Cannabis not only induces forgetfulness, it also opens the door for false memories, according to new research.
And that’s serious, man. It means the evidence of witnesses, victims and even alleged perpetrators of crimes could be less reliable – and open to legal challenge – if they have recently been under the influence of the most widely used illicit substance in the world.
The participants performed memory tasks soon after inhaling, and a week later.
In one, the subjects were asked to recall a list of words on a common theme. The cannabis users had a higher tendency to believe other related words had been on the list, when in fact they had not. That’s a classic test for false memory.
The subjects also witnessed a virtual reality fight and theft, and were asked questions about what they had seen.
Critically, the participants were fed misinformation about these scenarios through suggestive questioning, and by the false testimony of a second virtual witness.
Writing in the journal PNAS, the researchers report that participants who had inhaled THC were more likely to say “yes” to questions, indicating suggestibility, and had more false memories, especially while they were still intoxicated.