Hazy memories often come with smoking cannabis, but a recent study indicates something even more intriguing: cannabis might make those memories seem real, even when they’re not. It’s worth noting that despite being illegal as a Class B drug in the UK, cannabis has consistently been the most common illicit substance used in England and Wales since record-keeping started in 1995.
Researchers from Washington State University conducted a study involving 120 cannabis users, randomly assigning them to inhale either real cannabis with 20 or 40 milligrams of THC—the main psychoactive component—or a placebo. Participants then went through 21 memory tests, many of which hadn’t been used in previous cannabis research.
Results indicated that about 70% of participants experienced some degree of memory impairment after consuming THC. Among the worse effects noted were instances of false memories—recalling events or details that didn’t actually occur.
So, why do these ‘false memories’ occur?
Scientists propose that false memories emerge when the brain tries to piece together incomplete information. THC appears to weaken recall but maintain a sense of familiarity, leading people to feel certain about inaccurate memories. The researchers found that compared to placebo, cannabis use increased susceptibility to false memories and negatively affected various memory types, including verbal and visuospatial memory. Interestingly, they also noted no significant differences between those who took moderate and high doses.
Carrie Cuttler, an associate professor and co-author of the study, explained that memory creation and recall involve activating specific pathways in the brain. If THC disrupts this process, it could result in distorted memories. She mentioned that this research highlights acute cannabis use’s impact on everyday memory and functions, indicating that it broadly harms memory rather than selectively targeting specific areas.
However, Cuttler pointed out that the effects of THC on memory might not be as disruptive as alcohol. “Acute alcohol intoxication is generally more problematic for memory than cannabis,” she noted. Interestingly, the side effects from THC can diminish significantly after someone abstains from cannabis for about a month.
Common side effects from smoking weed
According to the Mayo Clinic, some other frequent side effects from marijuana use include:
- Altered senses, like enhanced color vision or more intense smells
- Changes in perception of time and space
- Mood changes and feelings of euphoria
- Challenges with thinking and problem-solving
- Impaired memory
- Confusion and disorientation
- Relaxation or sleepiness
- Dizziness
- Coordination issues
- Slowed reaction time
- Panic attacks
