It's Official: Marijuana Affects Decision Making


The stereotype of the marijuana smoker is a guy just sitting on the couch, unable or unwilling to make a decision on anything, except what kind of snack he wants.

Well, a new study has confirmed that smoking pot affects peoples' attention, memory, cognition and decision-making abilities.

Researchers from the Wake Forest Baptist Medical Center put 16 chronic marijuana smokers and 16 non-smokers through the Iowa Gambling Task (IGT), a complex decision-making test in which participants make choices, and win or lose money based on their choices. writes:

For the control group, after multiple exposures to early large monetary losses, they began to choose safer, less negative options on the task. In contrast, the marijuana users generally failed to alter their selection patterns and continued to make disadvantageous choices throughout the task. The researchers found that this was because marijuana users were less sensitive to the negative feedback during strategy development.

"The marijuana users appear to have a blunted response to losing. They don't figure out a strategy to avoid monetary losses and this is associated with a decreased functional brain response to the early, negative information that guides the other group to safer choices," said lead author Michael J. Wesley. "The bottom line is that it looks like they don't care as much if they lose."

These findings are seen as important because they demonstrate a potential negative side effect of chronic marijuana use.

"Understanding how marijuana influences the perception of what is 'negative' may help explain continued marijuana use and aid in the development of effective strategies for treatment therapies," Wesley said. "Published data suggests that marijuana use is increasing, both recreationally and medicinally. However, the misperception that it's harmless is also rising. It's imperative that we begin analyzing the effects of long term, heavy marijuana use."

The study is published in Psychiatry Research.

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