Drug beliefs produce a dose-dependent effect in the brain, study finds
Researchers have shown, for the first time, that a person’s beliefs about nicotine influences brain activity, producing a dose-dependent effect that was only thought to occur with pharmaceutical agents. In addition to providing an explanation for why individuals respond differently to the same drug, the findings suggest that pharmacological and nonpharmacological treatments could be optimized simply by leveraging the power of human belief.
Beliefs, the things we hold to be true about ourselves, other people, and the world we live in, can significantly influence our behavior and decision-making. However, the neural mechanisms driving how beliefs influence behavior are poorly understood. In an interesting new study, Mount Sinai Hospital researchers have shown, for the first time, that a person’s drug-related beliefs can influence their brain activity and behavioral responses similar to the dose-dependent effects seen with pharmaceuticals.
“Beliefs can have a powerful influence on our behavior, yet their effects are considered imprecise and rarely examined by quantitative neuroscience methods,” said Xiaosi Gu, corresponding author of the study. “We set out to investigate if human beliefs can modulate brain activities in a dose-dependent manner similar to what drugs do, and found a high level of precision in how beliefs can influence the human brain. This finding could be crucial for advancing our knowledge about the role of beliefs in addiction as well as a broad range of disorders and their treatments.”
Nicotine-dependent study participants were told that the nicotine strength of the e-cigarette they were about to use was either ‘low’, ‘medium’ or ‘high’ when, in reality, the nicotine content remained constant. After vaping, the participants underwent functional magnetic resonance imaging (fMRI) and performed a decision-making task known to engage neural circuits affected by nicotine.
The researchers found that the thalamus, a key binding site in the brain for nicotine, showed a dose-dependent response to the participant’s belief about nicotine strength. No other brain areas showed such a response, including the striatum, the area involved in decision-making and habit formation. They say the finding provides “compelling evidence” to support the relationship between subjective beliefs and a chemical’s effect on the brain, an effect that was previously only thought to apply to pharmaceutical agents.
The researchers also noted increased functional connectivity between the thalamus and the ventromedial prefrontal cortex (vmPFC), which has long been implicated in reward-related decision-making.
“Our findings provide a mechanistic explanation for the well-known variations in individual responses to drugs and suggest that subjective beliefs could be a direct target for the treatment of substance use disorders,” Gu said. “They could also advance our understanding of how cognitive interventions, such as psychotherapy, work at the neurobiological level in general for a wide range of psychiatric conditions beyond addiction.”
This research has the potential to improve how patients respond to medications.
“The finding that human beliefs about drugs play such a pivotal role suggests that we could potentially enhance patients’ responses to pharmacological treatments by leveraging these beliefs,” said Gu.
The researchers are keen to see what effects belief has on substances other than nicotine.
“We’re interested in testing the effects of beliefs on drugs beyond nicotine to include addictive substances like cannabis and alcohol and therapeutic agents like antidepressants and psychedelics,” Gu said. “It would be fascinating to examine, for example, how the potency of a drug might impact the effect of drug-related beliefs on the brain and behavior, and how long-lasting the impact of those beliefs might be.
"Our findings could potentially revolutionize how we view drugs and therapy in a much broader context of health.”
The study was published in the journal Nature Mental Health.
Source: Mount Sinai