- Personal Health Information & Self-Help
The science behind how to quit smoking with Dr. Steven Laviolette.
Due to changing attitudes and decades of education fewer and fewer people are taking up the habit of smoking cigarettes, but there are still many who do at least experiment with tobacco use.
Why is it some people can smoke for a while, and then give it up with minimal trouble, while others can struggle for decades without being able to quit and being addicted after minimal exposure?
Current research on this topic deals with the relationship between nicotine and a chemical messenger in the brain called dopamine and it is that relationship along with a person's genetics that largely will determine if a person will become a nicotine addict.
(More on this research can be found HERE)
To gain a little more insight into the future of research into nicotine addiction I spoke to Dr, Steven Laviolette, an associate Professor at the Department of Anatomy & Cell Biology at the University of Western Ontario, who is directly involved in the research.
The following is my discussion with Dr. Laviolette.
OK well let's get started...
First of all, let's put things at least in a biological sense in perspective: What is the normal function or purpose of our dopamine receptors, and just what is this dopamine stuff in the first place.
I am also curious as to why there would be such a contrast of responses in regards to nicotine exposure. Is there some other aspect of having the addiction prone receptors that is beneficial that would suggest why the trait seems to common? Does it maybe drive some other more positive behaviours?
Dopamine belongs to a class of neurotransmitters called the "monoamines" and at the present time, we know of two broad families of dopamine receptors called the "D1-like" and "D2-like" receptor subtypes. They differ in terms of their anatomical and functional distributions as well as their downstream molecular effects within the neuron.
What's interesting in terms of nicotine addiction, is that nicotine produces very aversive, unpleasant effects in many people during early exposure. In fact, a lot of clinical evidence suggests that how a person initially reacts to tobacco (e.g. likes it or hates it) goes a long way in predicting whether or not that individual will eventually get hooked. The problem of course is that many people, even though they find early nicotine experiences unpleasant, will keep up the smoking until it eventually becomes highly reinforcing. Once dependence is established, its often a case of smoking just to avoid the terrible feelings of withdrawal.
You raise a good point about the function of dopamine receptors. For many years we assumed that dopamine served as a "reward" signal exclusively, but we now know that dopamine is far more complex. In fact, as we showed in our 2003 paper in Molecular Psychiatry, the 'aversive' properties of nicotine are actually dependent on dopamine transmission.
Even more surprising to us, when we blocked dopamine transmission, the rewarding effects of nicotine were actually amplified! This did make sense however given other clinical evidence: patients with schizophrenia have very high rates of nicotine addiction and they are often medicated with the same dopamine receptor drugs we were using in our rodent model of nicotine reward conditioning.
So, we currently think that dopamine serves more as an "emotional salience" signal and when these receptors are blocked or activated, we can control the emotional or motivational value of a particular stimulus (e.g. nicotine) by either increasing, decreasing or in some way altering its emotional valence.
I am taking from what you are saying that desired effects would be achieved by chemically manipulating the receptor, correct?
Would this be something that could be used for other types of addiction?
Also, is there any danger of negative effects of manipulating the dopamine receptors that would adversely affect normal brain function?
For instance could it cause detachment in our interpersonal relationships,or does emotional bonding have a completely different set of rules?
..and maybe what people who struggle with being strongly addicted, is your research showing a definite path towards what could be rightly termed a 'cure' and broadly speaking, in terms of progress what sort of timeline are we looking at to seeing this as a reality?
Well the interesting thing about dopamine receptors is that we can often see opposite effects on behaviours and emotion by either blocking them with 'antagonist' drugs or activating them with 'agonist' drugs. In addition, we also reported in a recent paper published in Neuropharmacology, that chronic exposure to nicotine actually changes the functional effects of dopamine receptors. For example, in rodents that were previously naïve to nicotine, when we blocked dopamine receptors we made nicotine much more rewarding and addictive, just like our previous results. But once we made the rodents nicotine dependent by chronic nicotine exposure, now if we blocked dopamine receptors, the effect was to block the rewarding effects of nicotine. So, the role of dopamine transmission actually changes dramatically during the course of nicotine exposure. We've seen similar effects with opiate-class drugs like morphine and heroin so yes, there are similar effects of manipulating dopamine transmission for a wide variety of abused drugs.
In terms of negative effects, you're absolutely correct. Messing around with dopamine receptors is almost certain to produce some adverse reactions and dangerous side-effects. And unpredictable effects on emotional regulation is certainly a possible side effect. Right now, we are looking at targeting the downstream molecules that are under the control of dopamine receptor transmission. Sort of, going beneath the surface to find some interesting new pharmacological targets that may prove promising for clinical applications, and bypassing the potentially negative side effects related to dopamine transmission.
I do think that neuroscience research looking into addiction is definitely on the right path. Science has a wonderful way of correcting itself, if certain paradigms and previously believed theories turn out to be incorrect. I do anticipate that much more reliable and safer pharmacotherapeutics will be coming soon for the treatment of addiction. While a single 'cure' is unlikely, we are finding remarkable congruence in terms of the underlying neurobiological mechanisms related to addiction. Dopamine research is a great example of this convergence since we have found that nearly all drugs of abuse and even other stimuli that can lead to addictive-like behaviours can for the most part, cause dramatic effects on the brain's dopamine system. In terms of time lines, clinical research is a much slower process than what we can do at the basic research level, especially since clinical trials need to take place over years and various regulatory levels.
Having said that, I believe the next decade is going to be a very exciting one for neuroscience research into addiction.
As always, the biggest impediment to our progress is lack of research funding. We certainly hope that both the provincial and federal governments in Canada will continue to make addiction research funding a top priority and increase funding levels to reflect the massive cost to the healthcare system, and the economy in general, that addictions are causing.
Fantastic, sounds like a lot of possibilities over the next ten years or so. Hopefully the political will is still there to maintain the research to see it bear fruit.
In the meantime however, what if anything would be your best advice to someone who is heavily addicted to nicotine?
Absolutely. The most important thing for research is to keep the momentum going, and that takes investment in research. You know, I have many friends and relatives that are seriously addicted to tobacco. I've lost some of them to cancer as well, so I am strongly impelled to carry our research forward into translational treatments. There have been some new drug products aimed at treating nicotine addiction, albeit with limited success, but it seems that there are incremental improvements. Just as its rather mysterious as to why some people get hooked on nicotine and others don't, we often find that quitting is an equally mysterious process. Indeed, some folks really are quite successful at the old "cold turkey" approach. One interesting new development are the smokeless, electronic nicotine inhalers that mimic the act of smoking. I think this approach is quite promising because it gives a smoker the 'feeling' of smoking, not just the nicotine rush, but the act of holding the cigarette, drawing in the vapour, etc. Of course we'll have to wait and see how successful these new gadgets are but in the meantime, we'll keep plugging away at the underlying neurobiological mechanisms.
Some final thoughts
The thought of a cure for nicotine addiction is an exciting and intriguing one, and something that looks like it may not be all too far off in our horizon.
It is however, as Dr. Laviolette points out a matter of years and decades and so while there is light at the end of the tunnel there is nothing imminent.
Hopefully Dr. Laviolette's research, with the right focus and funding will bring us exciting new options before we know it and people will have a much easier time quiting.
In the meantime however, there are people who want to quit now and are having trouble doing so.
Hopefully this article will have given you a little more insight into your addiction and maybe why it might be it has a strong hold on you, while others may seem more free to take it or leave it as they please.
Nicotine addiction is both psychological and physiological, and the habit become ingrained in our lifestyle and daily routines as surely as it does our brain chemistry.
Just remember that while there are factors that can make it incredibly difficult to quit, that people manage to quit every day. Including those who are heavily addicted.
It is difficult but it is not impossible. Not at all. Maybe today that someone will be you?
Everyone of us is unique, and what works for and motivates one person may fall flat for another. For one person it might be noticing how much money it could save, for someone else it might be having someone in our lives that we want to be healthy for and that you want to show you love them more than cigarettes, for someone else they just might just be sick of always 'needing' a cigarette.
Whatever it is, make it yours and try whichever stop smoking aid you feel is right for you. Just please follow the instructions and don't fool yourself into thinking you have quit prematurely.
It takes a bit of time so be patient.
The worst that will happen is that you will have tried to do something good for yourself and maybe just a little more freedom.