Studies have suggested that negative emotions can trigger addictive substance use. Now, new research reveals that it’s not just bad feelings that make people crave an addictive substance. Instead, sadness in particular seems to drive the need to feed an addiction.
The research focused on smoking, but scientists in the fields of emotion and addiction are optimistic that it might generalize to other substances. The findings are particularly interesting in light of the epidemic of opioid use in communities facing a sense of loss, says Dacher Keltner, PhD, a psychologist at the University of California, Berkeley, who studies emotion but was not involved in the new study.
“To me, it’s just one of those revelatory papers,” Keltner says.
The research tackled the question of emotions and smoking behavior in four separate studies, ranging from an analysis of a nationally representative, longitudinal survey to a lab experiment investigating real smoking behavior (Proceedings of the National Academy of Sciencesopens in new window, Vol. 117, No. 2, 2020).
“We found converging evidence from very different datasets with all these different strengths, all pointing to the same message,” says Charlie Dorison, a PhD candidate in psychology at Harvard University. “All studies provided support for the same overarching hypothesis: sadness, but not all negative emotions, triggers tobacco use.”
Negative affect has long been suspected to boost cigarette cravings, as found in a meta-analysis led by Bryan Heckman, PhD, a psychologist at the Medical University of South Carolina (Addictionopens in new window, Vol. 108, No. 12, 2013). But Dorison and his colleagues wondered if they could be more specific. They’d previously found that sadness, more than other negative emotions, triggers spending and unhealthy eating, and wondered if the same might be true for substance use.
In their first study, the researchers used data from the Midlife in the United States survey (an ongoing project funded by the National Institute on Aging), with responses collected from 10,685 adult participants between 1995 and 2014. The results showed that participants who reported being sadder were more likely to be smokers at any given timepoint. Almost all of the smokers in the study had started before reaching adulthood, so the researchers couldn’t study smoking initiation. They did, however, see a correlation between sadness and smoking relapse after quitting: Individuals who were sadder in 1995 and in 2005 were more likely to be smoking again by 2014. Fear, anger and shame did not show correlations with smoking.
The researchers then recruited 425 smokers to participate in an online study in which they were asked about their cigarette cravings and then presented with one of three film clips designed to trigger sadness (a clip from the Pixar movie "Up"), disgust (a clip from 1996’s "Trainspotting") or neutral emotions (a documentary on furniture-making). After the clips, the participants did a short writing task to reinforce the induced emotion, and again answered questions about their cigarette cravings. Those who had watched the sad clip reported increased cravings compared to those in the neutral and disgust conditions.
In a third experiment, Dorison and his team drew from a behavioral economics approach, asking participants in an online sample whether they’d rather smoke sooner but take fewer puffs or smoke later but take more puffs. The participants (398 in the first experiment and 362 in a replication experiment) were randomly assigned to either the sadness or neutral video manipulations from the previous study.
Again, sadness seemed to trigger the need for a smoke. Smokers in the neutral condition said that they’d want 6.9% puffs more per every minute they had to wait for a cigarette. Smokers in the sadness condition required 8.1% puffs more per minute, an 18% increase in impatience.
That was an intriguing finding, but it was based only on hypotheticals. In the final study, Dorison and his team measured real smoking behavior. The researchers brought 158 smokers into the laboratory, subjected them to the same emotion manipulations and then measured their actual smoking behavior, including puff volume, velocity and duration. The smokers were required to abstain from cigarettes for eight hours before the experiment, so all were impatient to smoke; the effect of sadness on this craving was only marginally significant.
The researchers did, however, find that the sad smokers inhaled a 30% greater volume per puff than smokers in the neutral condition, explained by the smokers in the sadness condition taking longer drags on their cigarettes. The smokers in the sadness condition also became more self-focused, more negative overall and reported greater feelings of loss than those in the neutral condition. Only self-focus correlated with impatience to smoke. This finding fits in with the larger body of research that concludes sadness makes people more motivated to seek immediate rewards, Dorison says.
The finding that smokers who felt sadder inhaled more carcinogenic material is worth further research, says the Medical University of South Carolina’s Heckman, who was not involved in the study. “The fact that the puff volume was changing as a function of sadness has pretty major implications for potential harm exposure,” Heckman says.
Future research should delve deeper into testing other negative emotional states and how they interact, Heckman says. Sadness may not be the only negative emotion that triggers cravings, Dorison says, but it may be particularly potent. The team now has National Cancer Institute funding to study how emotion and decision-making findings might apply to public health.
“We’re interested in anti-smoking public service announcements that the Centers for Disease Control and Prevention puts out and looking at the emotions they use,” Dorison says. “If they harness sadness, they might unintentionally trigger a craving.”
Sadness, but not all negative emotions, heightens addictive substance use.
The researchers who conducted this study are:
- Thornton F. Bradshaw Professor of Public Policy, Decision Science, and Management at Harvard Kennedy School.
- Charlie Dorison, a PhD candidate in psychology at Harvard University.
- Keith Ericson, PhD, at the Questrom School of Business at Boston University.
- Ichiro Kawachi, MD, PhD, the John L. Loeb and Frances Lehman Loeb Professor of Social Epidemiology at the Chan School.
- Jennifer Lerner, PhD, the co-founder of the Harvard Decision Science Laboratory.
- Vaughan W. Rees, PhD, director of the Center for Global Tobacco Control at Harvard T.H. Chan School of Public Health.
- Ke Wang, a doctoral student at the Kennedy School.
