The Science behind Craving to Quit®
Our brains are set up to learn. From an evolutionary perspective, to survive, when we come upon a good source of food or water, it is helpful to remember where it is. When we stumble upon something dangerous, it is helpful to remember this too. And this reward-based learning system, that is conserved all the way back to the most primitive of nervous systems (the sea slug with roughly 20,000 neurons), in its most basic form has three elements: trigger, behavior, reward. We see berries, we eat them, and if they taste good (reward), we lay down a memory to come back for more.
Fast forward to modern day, where food is plentiful, and our environment is relatively safe, our brains still have the same reward-based learning system. Under the names of operant conditioning, associative learning and positive and negative reinforcement, a lot more is known about how it works. This is the good news.
The bad news is that over time, humans have stumbled upon substances that literally hijack this reward-based learning system. In fact, every substance of abuse from tobacco to crack cocaine affects the same brain pathways –the mesolimbic pathway which mainly acts through the neurotransmitter dopamine. And each time we do a line of cocaine and feel the high or smoke a cigarette when we are stressed out and feel better afterwards, we reinforce the “habit loop” (see Figure). This combination of tapping into the dopamine system and behavioral repetition is deadly –for example smoking is the leading cause of preventable morbidity and mortality in the US.1
Treatments such as cognitive behavioral therapy are thought to act through the prefrontal cortex –involved in reasoning, planning and “top down” cognitive control in general. When we know we shouldn’t eat that second helping of cake or smoke a cigarette, this is the part of the brain that helps us control that urge. Unfortunately, like the rest of the body, the prefrontal cortex is subject to fatigue, described by some as “ego depletion.”2 As the HALT acronym predicts, when we are Hungry, Angry, Lonely, or Tired, we are more susceptible to smoking or using drugs. This may be because, as the youngest part of the brain from an evolutionary standpoint, this is also the first cortical region to go “offline” when we are stressed or otherwise depleted.3
If we can’t rely on our prefrontal cortex, are there other ways to change our behaviors?
Interestingly, mindfulness training, seems to be emerging as a possible solution. Based in ancient Buddhist psychology, mindfulness helps individuals pay careful attention to their cravings, such that they can see what they are made up of –thoughts and body sensations. Importantly, with this awareness, they can notice cravings as they arise, see how they change from moment to moment (instead of lasting “forever” as some of my patients have described), and as a result, stay with them and ride them out instead of acting on them. Also, paying attention also helps individuals see clearly what they are getting from their behavior in that moment.
For example, a person in our smoking program commented, “Mindful smoking: smells like stinky cheese and tastes like chemicals. YUCK!” She noticed that smoking wasn’t as great as she might have convinced herself previously. And this is the beginning of the end –we start to get disenchanted with what we were doing –just by paying careful attention. This dual purpose of mindfulness -disenchantment and being able to be with ourselves instead of reacting automatically -may be a winning combination.
We, and others have found that mindfulness training helps individuals with a range of addictions from alcohol to cocaine to nicotine dependence.4 In fact, in one randomized clinical trial, we found that it was twice as good as gold standard treatment (American Lung Association’s Freedom From Smoking) in helping people quit and stay quit5 Why would it work so well? It turns out that it targets the core addictive loop –by helping people ride out their cravings instead of acting on them, it decouples the link between craving and smoking, effectively dismantling the loop. 6 This is an important point, because these data pinpoint a mechanistic link that is being targeted by mindfulness, which is not always easy to find in behavioral treatments.
- Center for Disease Control and Prevention. Smoking-Attributable Mortality, Years of Potential Life Lost, and Productivity Losses --- United States, 2000--2004. MMWR Morbidity and Mortality Weekly Report 2008 [cited 2011 November 17].
- Muraven, M. and R.F. Baumeister, Self-regulation and depletion of limited resources: does self-control resemble a muscle? Psychological bulletin, 2000. 126(2): p. 247-59.
- Arnsten, A.F., Stress signalling pathways that impair prefrontal cortex structure and function. Nat Rev Neurosci, 2009. 10(6): p. 410-22. PMCID: 2907136.
- Brewer, J.A., H.M. Elwafi, and J.H. Davis, Craving to quit: Psychological models and neurobiological mechanisms of mindfulness training as treatment for addictions. Psychol Addict Behav, 2013. 27(2): p. 366-79. PMCID: 3434285.
- Brewer, J.A., S. Mallik, T.A. Babuscio, C. Nich, H.E. Johnson, C.M. Deleone, C.A. Minnix-Cotton, S.A. Byrne, H. Kober, A.J. Weinstein, K.M. Carroll, and B.J. Rounsaville, Mindfulness training for smoking cessation: Results from a randomized controlled trial. Drug and Alcohol Dependence, 2011. 119(1-2): p. 72-80. PMCID: 3191261.
- Elwafi, H.M., K. Witkiewitz, S. Mallik, T.A.t. Thornhill, and J.A. Brewer, Mindfulness training for smoking cessation: moderation of the relationship between craving and cigarette use. Drug Alcohol Depend, 2013. 130(1-3): p. 222-9. PMCID: 3619004.
- What's next for smoking cessation: mindfulness! Psychiatric Times, 2013
- How Mindfulness Breaks the Habit Loop, Grand Rounds at Yale, 2013
- Harvard Mental Health Newsletter about Dr. Brewer's smoking study, 2012
- Journal Watch, "Mindfulness Reduces Smoking," Psychiatry, 2011
on how we get in our own way