How the brain responds to nicotine may depend, at least partially, on how much nicotine the smoker thinks is in the cigarette, according to a new study by the Center for BrainHealth at the University of Texas at Dallas.
The findings, published in the journalFrontiers in Psychiatry, show that smoking a nicotine cigarette but believing that it lacked nicotine was less satisfying than smoking a cigarette that was known to have nicotine. In other words, in order to satisfy nicotine cravings, smokers had to not only smoke a cigarette with nicotine but also believe that they were smoking nicotine.
“These results suggest that for drugs to have an effect on a person, he or she needs to believe that the drug is present,” said Dr. Xiaosi Gu, assistant professor in the School of Behavioral and Brain Sciences and the study’s lead author.
The researchers used functional magnetic resonance imaging (fMRI) to monitor neural activity in the insula cortex, a region of the brain associated with drug cravings and addiction. It also plays a role in diverse functions such as bodily perception and self-awareness.
The double-blind study involved 24 chronic, nicotine-addicted smokers. Over four visits, participants were twice given a nicotine-containing cigarette and twice a placebo. With each type of cigarette, they were once correctly told what type they had and once told the opposite.
“We examined the impact of beliefs about cravings prior to and after smoking while also measuring neural activity,” said Gu, who also serves as the head of the Computational Psychiatry Unit at the Center for BrainHealth.
During each visit, participants underwent an fMRI scan and were given a cigarette, but each visit tested a different condition: the participant believes the cigarette contains nicotine but receives placebo; believes the cigarette does not contain nicotine but receives a nicotine cigarette; believes the cigarette contains nicotine and receives nicotine; believes the cigarette does not contain nicotine and receives placebo.
After smoking each cigarette, participants completed a reward learning task while undergoing fMRI. They rated their levels of craving before smoking the cigarette and after.
The fMRI scans showed significant neural activity that correlated to both craving and learning signals when subjects had smoked a nicotine cigarette and had been told that it contained nicotine. However, smoking nicotine but believing it was a placebo did not produce the same brain signals.
The new study supports prior research showing that beliefs can alter a drug’s effects on craving, providing insight into potential avenues for new drug addiction treatments.
Source: Center for BrainHealth