Study suggests that belief is as important as biochemistry in addiction

smoking
Credit: Vera Kratochvil/public domain

(Medical Xpress)—Are there more than biophysical factors at play in addiction? A new study by Xiaosi Gu and Terry Lohrenz from Virginia Tech Carilion Research Institute in Roanoke shows that cognitive beliefs play a significant role in a person's neurological response to an addictive substance and that belief can diminish the neurological effects of an addictive drug. Their research is reported in The Proceedings of the National Academy of Sciences.

While addictive substances target certain neurological pathways, seems to be more than a mere biochemical response to a drug. Different people respond to addictive substances in different ways, indicating that there must be other mechanisms to account for these differences.

Addiction is a complex phenomenon because, while addictive substances all target the mesolimbic dopaminergic pathway, some people seem to have a stronger neurological response to than others. Furthermore, addiction appears to be more complex in humans than rodents. Rodents respond with less interest in the addictive substance when their dopaminergic pathway is suppressed, while humans tend to have mixed results with biochemical suppression, indicating that both cognitive and biochemical factors are likely at play in .

Gu and Lohrenz tested the impact of subject beliefs regarding an addictive substance by investigating computational and neural learning signals using computational modeling and model-based functional magnetic resonance imaging (fMRI) in 24 chronic smokers in a within-subject balanced placebo experiment.

The test subjects were given a cigarette either with or without . Half of the subjects were told that the cigarettes contained nicotine even though some did not; the other subjects were told that the cigarettes did not have nicotine even though some did. Subjects were tested on four separate occasions. Each smoked a cigarette immediately before an fMRI session. Each time, the test subjects were given a sequential market task based on a quantitative model that tests both non-choice dependent behavior and choice-dependent behavior. The task involved betting, and then experiencing a change in the market price to obtain a gain or loss.

Gu and Lohrenz's team found that when test subjects believed that there was no nicotine in the cigarette, the neurological response to choice behavior questions was similar to those who did have nicotine. Those who knew that they smoked a nicotine-containing cigarette had a different neurological response. In other words, the belief that they were not smoking nicotine diminished the of nicotine. Additional tests showed that subjects who believed they had ingested nicotine demonstrated different reward prediction signals whether the person had smoked a nicotine-containing cigarette or not.

In order to see whether this effect was specific to learning pathways, Gu and Lohrenz's team investigated whether cognitive belief affected visual attention signals. They found no significant changes in visual attention signals whether or not a subject was told that they were smoking nicotine, thus confirming that the effects are specific to value signal and reward prediction error signal, or to the learning pathways.

This study provides quantitative evidence that belief in nicotine's efficacy plays a much larger role in its effects on neurological systems than was previously thought and supplements prior studies with alcohol and cocaine addiction. This evidence implies that our understanding and treatment of addiction may need to be modified to account for the effects of cognitive belief.

While activating the mesolimbic dopaminergic pathway plays a role in physical dependence, it cannot be the only cause of addiction. The authors conclude that "cognitive beliefs could be as potent as pharmacological interventions in terms of modifying biophysical processes in the brain and changing behavior in addicted individuals." They contend that manipulating a person's beliefs about an addictive substance may be one avenue for treating addiction .


Explore further

E-cigarettes less addictive than cigarettes, according to study

More information: Belief about nicotine selectively modulates value and reward prediction error signals in smokers, Xiaosi Gu, PNAS, DOI: 10.1073/pnas.1416639112

Abstract
Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers' prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers' beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of "no nicotine in cigarette" (compared with "nicotine in cigarette") strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers' choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems.

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Citation: Study suggests that belief is as important as biochemistry in addiction (2015, January 22) retrieved 17 July 2019 from https://medicalxpress.com/news/2015-01-belief-important-biochemistry-addiction.html
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User comments

Jan 22, 2015
what meaningless inconclusive research. so people aren't robots and drugs aren't passwords.

Jan 22, 2015
The authors of the study apparently think that a smoker can be tricked into believing a cigarette with nicotine has no nicotine and that a cigarette with no nicotine has nicotine.

That is as likely as making someone believe he is in the dark when he can see the light.

People who are addicted to a substance know when they are consuming the substance and when they are not.

Jan 22, 2015
This gives strong support for the A.A. methodology which I can attest is very affective with realistic belief conditioning. It isn't necessary to begin with believing anything, just suspending disbelief.

Jan 23, 2015
The authors of the study apparently think that a smoker can be tricked into believing a cigarette with nicotine has no nicotine and that a cigarette with no nicotine has nicotine.

That is as likely as making someone believe he is in the dark when he can see the light.

People who are addicted to a substance know when they are consuming the substance and when they are not.


And yet a placebo can be efficacious?

Jan 23, 2015
fadingfool,
And yet a placebo can be efficacious?


Of course, but not if you are trying to fool someone who is addicted to a substance that the placebo is the addictive substance.

Jan 25, 2015
what meaningless inconclusive research. so people aren't robots and drugs aren't passwords.


Well, they had some mice over from a previous experiment, were bored and decided that they needed a fun reason to vivisect a few of them :)

Feb 28, 2015
So, what does this study prove about the causes of beliefs and addiction as found by measuring the subjects' brains?

Well, nothing, really. The study is all about the effects, the symptoms. There is nothing there about underlying conditions and causes, nothing about what primarily drives people's beliefs and addiction behaviors.

What did the study's peer reviewer see there that factually advanced science? Everybody already knew that beliefs can substitute for addicting substances and temporarily change behavior. That is a foundation of AA and detox centers.

It's also foundational that these beliefs have to be constantly reinforced. In my opinion, that in and of itself is proof that underlying causes have not been addressed. The symptoms are always bubbling up, requiring interventions in order to stay suppressed.

http://surfaceyou...ealself/

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