Summary: Researchers have found that what people believe about a drug can alter their brain activity and behavior in ways that mirror the dose-dependent effects of the drug itself.
A Mount Sinai study that focused on beliefs about nicotine demonstrates that human expectations operate with surprising precision and can produce dose-like effects in the brain. By telling participants they were using different nicotine strengths while keeping the actual nicotine level constant, researchers used functional neuroimaging to reveal brain responses that scaled with those beliefs. These results have important implications for addiction treatment, mental health research, and the design of therapeutic interventions that harness expectation and belief.
Key Facts:
- Beliefs about drugs can modulate brain activity and behavior in a dose-dependent manner, much like pharmacological effects.
- The thalamus—a principal site for nicotine binding—showed responses that scaled with participants’ beliefs about nicotine strength.
- Belief-driven modulation of brain circuits, including thalamus–prefrontal connectivity, points to new targets for addiction treatments and broader psychiatric interventions.
Source: Mount Sinai Hospital
Mount Sinai researchers have for the first time shown that a person’s beliefs about drugs can produce dose-dependent changes in their brain activity and behavior similar to pharmacological effects.
The study centered on nicotine beliefs and explored how expectations influence the neural mechanisms that underlie addiction and decision-making. These findings suggest that beliefs are not merely vague psychological effects but can exert precise, measurable influence on brain regions and networks involved in substance response and reward processing. The research was published in the journal Nature Mental Health.
“Beliefs can have a powerful influence on our behavior, yet their effects are often viewed as imprecise and rarely tested with quantitative neuroscience methods,” says Xiaosi Gu, PhD, Associate Professor of Psychiatry and Neuroscience at the Icahn School of Medicine at Mount Sinai and senior author of the study. “We wanted to see whether human beliefs could modulate brain activity in a dose-dependent way similar to drugs, and we found clear, precise effects.”
To test this idea, the research team instructed nicotine-dependent participants that an e-cigarette they would vape contained either low, medium, or high nicotine strength; in reality, the nicotine level was held constant across all conditions. Participants then completed a decision-making task known to engage nicotine-sensitive neural circuits while undergoing functional MRI scanning.
The team observed that the thalamus—a key brain site for nicotine binding—responded in a graded, dose-dependent manner to participants’ beliefs about nicotine strength. In other words, subjective expectation alone produced neural responses that tracked with the indicated strength, even though the actual nicotine dosage was unchanged. This provides compelling evidence of a direct link between belief states and biological substrates in the human brain.
Additionally, belief strength parametrically altered functional connectivity between the thalamus and the ventromedial prefrontal cortex (vmPFC), a region essential for decision-making and valuation. This connectivity change further supports the idea that beliefs shape not only local brain activity but also the communication between brain regions involved in cognitive and affective processes.
“Our results offer a potential mechanism for the well-known variability in individuals’ drug responses,” notes Dr. Gu. “They also point to subjective beliefs as a potential direct target in treating substance use disorders. More broadly, understanding how beliefs alter brain circuits can illuminate how cognitive therapies and other nonpharmacological interventions exert neurobiological effects across psychiatric conditions.”
Dr. Gu, a leading researcher in computational psychiatry, highlights clinical applications: by systematically leveraging expectations, clinicians might amplify the effectiveness of pharmacological treatments or refine behavioral therapies. The findings could inform how clinicians frame information about medications and how belief-based strategies are incorporated into treatment plans.
The Mount Sinai team also plans to investigate belief effects across other substances and therapeutic agents, including addictive drugs like cannabis and alcohol as well as medications such as antidepressants and psychedelics. Future research will examine how the perceived potency of a drug interacts with belief-driven brain responses and how long-lasting these effects can be. Such work has the potential to reshape our understanding of drug response and therapeutic benefit from a combined pharmacological and cognitive perspective.
About this psychology, belief, and neuropharmacology research news
Author: Elizabeth Dowling
Source: Mount Sinai Hospital
Contact: Elizabeth Dowling – Mount Sinai Hospital
Image credit: Neuroscience News
Original Research: Closed access. “Nicotine-related beliefs induce dose-dependent responses in the human brain” by Xiaosi Gu et al., Nature Mental Health
Abstract
Nicotine-related beliefs induce dose-dependent responses in the human brain
Beliefs exert powerful influences on behavior, yet their neural mechanisms are not fully understood. This study tested whether beliefs could affect brain activity in a manner analogous to pharmacological dose-dependent effects.
Nicotine-dependent participants were told that the nicotine strength in an electronic cigarette was “low,” “medium,” or “high,” while the actual nicotine content remained constant. After vaping, participants completed a decision-making task during functional neuroimaging that recruits circuits sensitive to nicotine.
Beliefs about nicotine strength produced dose-dependent responses in the thalamus, a key nicotine binding site, while similar effects were not observed uniformly across all brain regions. Nicotine-related beliefs also modulated connectivity between the thalamus and the ventromedial prefrontal cortex, a region implicated in decision-making. These results demonstrate a high level of precision in how beliefs influence the brain, offering mechanistic insight into individual differences in drug responses and highlighting the pivotal role of beliefs in addiction and treatment.