Understanding how graphic warnings on cigarette packs impact brain activity may shed light on how they can help smokers quit.
Co-lead study author Darren Mays, PhD, an assistant professor of oncology at the Lombardi Comprehensive Cancer Center at Georgetown University in Washington, DC, and colleagues publish their findings in the journal Addictive Behaviors Reports.
Smoking is the leading cause of preventable death in the US, responsible for killing more than 480,000 Americans every year.
According to the Centers for Disease Control and Prevention (CDC), smoking increases the risk of coronary heart disease and stroke by two to four times and raises the risk of lung cancer by around 25 times.
Statistics like these emphasize the need for strategies to reduce smoking rates, and one such strategy has been the introduction of graphic warning labels (GWLs) to cigarette packaging.
To date, GWLs on cigarette packaging have been implemented in more than 65 countries, spurred by increasing evidence that the warnings help smokers consider the health risks and may even help them quit the habit.
The US Food and Drug Administration (FDA) proposed the implementation of such warnings in 2009, though legal challenges from tobacco companies delayed the process. It is now unclear when the federal agency will action their proposals.
Brain scans measured neurological response to GWLs
For their study, Mays and colleagues sought to determine the underlying biological mechanisms that might explain why GWLs on cigarette packaging encourage smokers to think about the health consequences.
The team showed 19 current smokers aged 18-30 a series of images of either GWLs - consisting of a graphic and text - text-only warning labels or plain cigarette packaging for 4 seconds each.
The GWLs included an image of an open mouth with rotted teeth and a tumor on the lower lip, for example, alongside some text that said: "WARNING: cigarettes cause cancer." The images included some of those proposed by the FDA that warn of the smoking-related risks for stroke, heart attack, cancer and lung disease.
The team used functional magnetic resonance imaging (fMRI) to scan the brains of each participant as they viewed the warnings, allowing them to analyze brain activity.
Additionally, the subjects were required to use a push-button control after viewing each image to state how much each one made them want to quit smoking, ranging from 1 (not at all) to 4 (a lot).
GWLs induced activity in emotional, decision-making brain regions
The team found that GWLs were much more likely to motivate participants to quit smoking than text-only warnings and plain packaging.
- Smoking is responsible for around 90% of lung cancer deaths in men and women
- Around 80% of deaths from chronic obstructive pulmonary disease (COPD) are caused by smoking
- Smoking harms almost every organ in the body.
Furthermore, when the subjects viewed the GWLs, they demonstrated activity in certain areas of the amygdala and the medial prefrontal cortex of the brain.
Co-lead study author Adam Green, PhD, of the Department of Psychology at Georgetown, explains that the amygdala responds to stimuli that are emotionally powerful, especially fear and disgust, which are emotions that often influence decision-making.
"The medial prefrontal region that responded to graphic warning labels in this study has been previously associated with self-relevant processing," Green adds. "When we find information to be self-relevant, that may increase how impactful it is for our life decisions."
Previous research has also suggested that brain activity in both the amygdala and medial prefrontal cortex might influence future decisions and attitudes related to health.
"What we found in this study reinforces findings from previous research where scientists have asked participants to report how they think and feel in response to graphic warnings on cigarettes," says Mays. "The study offers us new insights on the biological underpinnings for those responses, bolstering evidence for how these warnings can work to motivate a change in behavior."
Senior study author Raymond S. Niaura, director of science at the Schroeder Institute for Tobacco Research and Policy Studies at Truth Initiative in Washington, DC, adds:
"Regulators can and should use this research to craft more effective warning labels and messages to smokers that both deliver facts about the negative effects of smoking, and trigger thoughts and actions that move smokers toward quitting.
Tobacco is still the leading preventable cause of death in the US and the growing body of research showing the effectiveness of warning labels should energize policy-making."
In April 2015, a study reported by Medical News Today suggested that GWLs on cigarette packaging help increase young adults' knowledge about the dangers of smoking.