It's been 50 years since the U.S. surgeon general's report on smoking and health spurred one of the largest public health behavior changes success stories of the 20th century. Before and since this groundbreaking report's release, psychology has been at the forefront of smoking cessation efforts. Research into the biological and behavioral mechanisms of addiction has led to many successful treatments for nicotine addicts. In this episode, we talk with Dr. Sherry McKee, a researcher whose work has focused on gender differences and smoking. She discusses why women have a harder time kicking the habit and what science can do to help them quit.
Sherry McKee has been working on finding out why women have a harder time quitting smoking than men. Her work focuses on the role stress and depression play in smoking behaviors for both men and women. She is director of the Yale Behavioral Pharmacology Laboratory. She's also an associate professor of psychiatry at the Yale School of Medicine. Her smoking research has been funded by the Office of Research on Women's Health and the National Institute of Drug Abuse. Thank you for joining us, Dr. McKee.
SHERRY MCKEE: Thank you for having me.
AUDREY HAMILTON: Is there a critical health disparity among female smokers and if so, what is being done to address that?
SHERRY MCKEE: There are critical health disparities among women smokers. Smoking is still the leading cause of preventable morbidity and mortality in the U.S. Obesity is second. Alcohol use is third. We know that across industrialized nations, women smokers are going to be responsible for a half million deaths per year and this rate is expected to exponentially increase over the next 25 years.
Now with regards to their health effects, when you equate tobacco exposure between men and women, women are more susceptible to serious tobacco-related disease. And this includes things like lung cancer and heart disease. Women also experience sex-specific health risks, primarily related to their reproductive health. So, they have problems with their menstrual cycle. They enter menopause earlier. And, of course, women who smoke during pregnancy have a whole host of pregnancy-related negative or adverse events. Things like preeclampsia and then lower birth-rate babies.
So, in addition to women experiencing more health-related effects of smoking, women are also less able to quit smoking. There's the national data that's being collected over the last forty years and every single year for the last forty years quit rates for women are lower than quit rates for men. Now compounding this problem, currently available medications are not as effective, or generally not as effective, for women smokers. To some extent, all of these medications, which are approved by the FDA, all target the nicotinic receptor in the brain, and this might not be the optimal strategy for women.
AUDREY HAMILTON: So, it's interesting to learn that women have more difficulty quitting smoking than men given that the CDC has said women tend to be more health-conscious than men. You know, you would think that quitting smoking would be easier. Can you tell us what you've learned about why this is not the case?
SHERRY MCKEE: Well, there have been a number of factors identified that are thought to underlie why women have more difficulty quitting smoking. These include things like factors related to their menstrual cycle. Also, smoking to manage their weight and smoking to regulate their negative mood and stress.
AUDREY HAMILTON: Part of your work focuses on tailoring treatments for women who are trying to quit. Why do you think gender-specific treatments can work and could you provide an example?
SHERRY MCKEE: Sure. To develop effective treatments for women smokers we need to target factors which underlie their smoking behavior. Now, this is a bit of a generalization, but across a number of studies, we know that women generally smoked to regulate negative mood and stress, more so than men. That's not to say that men don't smoke when they're stressed, but this is more true for women than it is for men.
And when you look at men, they tend to smoke more for the reinforcement that they receive from nicotine. And again, this is not to say that women don't also receive reinforcement for nicotine, but it's not as strong as a factor that motivates their smoking as it is for men.
So, we are currently targeting what's called the "norge nergic" system in the brain to understand if this is an important focus for developing medications to treat smokers. From animal studies, we know that this system is involved in stress responses and it's also involved in the reinforcement from nicotine. We feel that medications targeting this system may be effective for both women and men, but might operate through different mechanisms. And our initial studies have shown this to be the case. We've studied a medication called "guanfacine," which was originally developed as a blood pressure medication. In smokers, we have shown that it decreases smoking in men and women, but that it tends to reduce the effect of stress and the negative effect that stress has on smoking behavior, more so for women. And then, it also tends to reduce nicotine-related reinforcement more so for men. We are excited by the potential of this research to improve quit rates for both women and men.
AUDREY HAMILTON: So you're talking a lot about how stress relates to smoking. What do we know about how stress impacts smokers and their ability to quit?
SHERRY MCKEE: Stress is a primary reason why people continue to smoke and also, it's a primary reason why people relapse back to smoking. Most smokers want to quit smoking. If you ask a smoker, you know, if they want to quit, they'll say yes. And then you ask them about their current plans to quit and they'll say well now's not a good time. I have a big deadline at work. My kids are really stressing me out. They'll identify some barriers that prevent them from engaging in a quit attempt and very often they're stress related. We know that stress has a larger effect on women smoking than men. We've conducted a number of laboratory studies where we bring men and women into the lab, we stress them out and we find that women reach for cigarettes much more quickly than men and they smoke them much more intensely when they're stressed. So, they inhale more deeply and they also take more puffs from a cigarette.
AUDREY HAMILTON: What about depression and smoking? How prevalent is smoking among people with depression and what's being done to help clinically depressed people who are addicted to cigarettes?
SHERRY MCKEE: Right now in the U.S., about eight percent meet criteria for major depression and about 40 percent of these people smoke. So, it's a huge number. This is double the rate of smoking among U.S. adults, which is currently at about 20 percent. We know that individuals with depression have more difficulty quitting. Yet, very little is known about how best to help them stop smoking. We've conducted a review of the research that's being conducted and we found that most smokers that are studied have lifetime diagnosis of depression versus, so they had depression at some point in their past versus being currently depressed. So those that are currently depressed have not been a huge focus of the research. Additionally, most studies will exclude, even if they're studying depressed smokers, they'll exclude people who are currently taking a medication or an anti-depressant to help treat their depression. We know that depression seems to have a greater negative impact on women and their ability to quit smoking, across a few of these studies. Yet, the studies, or the majority of studies do not focus on comparing men and women. There are some studies which suggest that adding a component to help people manage their mood states can be effective and can help improve rates of people being able to quit. But, we know that smokers with depression have more severe tobacco withdrawal symptoms, experience more craving and these factors could be targets of future treatment development.
AUDREY HAMILTON: Talking about nicotine and you mentioned stress and depression. You know, obviously nicotine plays a role. It's addictive. We know that. Some people have called for tobacco companies to lower nicotine levels in cigarettes. Do you think this could work in helping people stop smoking or is there more of a behavioral component to smoking that will also need to be addressed to help people quit?
SHERRY MCKEE: That's a really interesting question. The FDA has funded research examining the impact of lower nicotine cigarettes on smoking behavior and also toxin exposure. We know that women's smoking is less motivated by nicotine and more influenced by what's called "non-nicotine factors," such as sensory factors like the sight and the smell of a cigarette. So in this work that's being funded by the FDA, it will be critical to investigate whether women and men react differently to these lower nicotine cigarettes.
AUDREY HAMILTON: Well, thank you. This has been very interesting. I appreciate you coming and talking with us, Dr. McKee.
SHERRY MCKEE: Thank you for having me.
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