'Beliefs can be just as powerful as nicotine'

Belief alone may erase or enhance the effects of nicotine in people under the influence of the active drug, a new study suggests.
In the study, participants inhaled nicotine, yet they showed significantly different brain activity, researchers said.
"Our research group has begun to show that beliefs are as powerful a physical influence on the brain as neuroactive drugs," said Read Montague, director of the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute and lead author of the study.
Nicotine has formidable effects throughout the brain, especially in the reward-based learning pathways. Nicotine teaches the brain that smoking leads to reward.

Once the brain learns that correlation, the addictive chemical cycle is difficult to break.
In this study, scientists tracked the brain responses using functional magnetic resonance imaging.

"We suspected that we would be able to see neural signals based on the subjects' belief rather than their actual nicotine intake," said Montague.
After smoking cigarettes, volunteers played a reward-based learning game while their brains were scanned. The subjects viewed a historical stock price graph, made an investment, and repeated the cycle multiple times.
Researchers used computational models of learning signals thought to be generated by the brain during these kinds of tasks. In each subject, the individually tracked signals were specifically influenced by beliefs about nicotine.

Montague and his team found that the people who believed they had smoked nicotine cigarettes made different choices and had different neural signals than the other participants, despite the fact that both groups had consumed the same substance.
The scientists also found people who believed they had smoked nicotine had significantly higher activity in their reward-learning pathways. Those who did not believe they had smoked nicotine did not exhibit those same signals.
"It was the belief alone that modulated activity in the learning pathway. This goes beyond the placebo effect," Montague said.
Multiple studies support the placebo effect, showing sham treatments can improve a patient's condition simply because the person believed it would be helpful.

In the current study, however, researchers found belief alone could actually erase or enhance the effects of nicotine in participants who were under the influence of the active drug.
The study was published in the journal PNAS.