Drug and Gambling Addiction, and Anti-Nicotine and Anti-Cocaine Vaccines
In this show, guests include Dr Campbell Bunce, from Xenova, who joins us to talk about vaccines to prevent nicotine and cocaine addiction, Cambridge University psychology professor Barry Everitt, who works on the brain mechanisms of addiction, and Prof. Lawrence Whalley, from the University of Aberdeen, who has been looking into how smoking can dimish brain power as you age. Also joining us on the show is Prof. Mark Griffiths, from Nottingham Trent University, the only professor of gambling addiction in the UK, who asks whether gambling can genuinely be considered an addiction, like nicotine or heroin.
In this episode
- An Anti-smoking And Anti-cocaine Vaccine
An Anti-smoking And Anti-cocaine Vaccine
with Dr. Campbell Bunce Campbell - We've come up with a novel way to help addicts kick both the smoking and cocaine habit: a kind of anti-addiction vaccine. Using the vaccine helps to prevent the high people get from t
Chris - So how does the vaccine work?
Campbell - The basis behind the vaccine is that it stimulates the immune system to generate antibodies towards nicotine or cocaine. Antibodies are very large proteins and bond specifically to nicotine or cocaine. When the antibody meets nicotine, it binds to it and prevents the nicotine molecule from getting into the brain. Normally, nicotine and cocaine molecules are very small, but when they are bound to the very large antibodies, they can no longer cross the blood-brain barrier. The antibody complex acts like a sponge that maintains nicotine in the bloodstream and stops it getting to the brain and giving the addict a high. If people stop getting high, then hopefully it will break the habit.
Kat - How would this work in tandem with people trying to quit the physical habit? Many people say it has just become part of their behaviour.
Campbell - That's a difficult question to answer until we do some formal testing. However, there are two main aspects to quitting: firstly come withdrawal symptoms. These are often experienced soon after the addict decides to quit, and can take many forms. After that, those that give up are at risk of a relapse. This usually happens when people are in an environment in which they experience all the cues they associate with the drug-taking habit. This might be by going into a pub, having a drink in their hand and then wanting to reach for a cigarette. They re - experience the pleasure of their old habit and can slip back into regular use. If the person is vaccinated, it will prevent the hit from the moment of weakness and stop the reinforcement of the habit.
Chris - When you inject something into somebody, it produces an immune response and creates antibodies. Seeing as many people smoke cigarettes for years, how come they don't have antibodies for nicotine already?
Campbell - The immune system has evolved to spot the difference between itself and foreign proteins. However, very small molecules (such as nicotine and cocaine) can evade the immune system, as they are too small to be recognised. In designing the vaccine, we had to think of a way to allow the immune system to recognise the molecules. We found that it can recognise small molecules when they are attached to much larger immunogenic proteins. The vaccine is designed to physically attach small molecules to a very large protein. This fools the immune system into making antibodies against things it wouldn't see otherwise, and thus raises an immune response.
Kat - How long will the response last for?
Campbell - The most effective vaccines tend to be live forms of the infectious disease. As you go down the scale, you get protein vaccines, which are less able to get a strong and long lasting immune response. Our vaccine is even further down the scale as it looks at very small molecules. What we've found in the clinic so far is that we can raise a reasonably high antibody response towards nicotine and cocaine. The antibodies generally persist for about 6 months.
Chris - So the nicotine locks on and can't get through to the brain, but then what happens? Does the nicotine leach off or get burnt up somewhere?
Campbell - What the antibodies do is protect the drug from the normal metabolism that it is usually subjected to. Nicotine in a vaccinated subject should have its half life increased two-fold, meaning that it is burnt up faster. It should be a very dynamic interaction.
Chris - Will it be possible to vaccinate someone who has never smoked before?
Campbell - Yes, it would. Theory would suggest that they wouldn't get a high from smoking and therefore wouldn't become addicted.
Chris - If there is only so much nicotine the antibody can soak up, then surely if someone smoked lots and lots of cigarettes, they would still get a hit. Will this vaccine not encourage people to smoke more?
Campbell - That is one of the most asked questions. There is a concern that it is possible to overcome the antibodies, but we haven't seen anything like that happen in our trials so far.
Kat - Do people injected with the vaccine say they report less of a high?
Campbell - We have not accurately measured self-reported pleasure. When people have relapsed, we simply asked them whether they get more, less or the same amount of pleasure as they did before. From those we have asked, a high proportion report a reduction in pleasure. This should make people feel less inclined to continue.
- How Smoking Harms your IQ in Old Age
How Smoking Harms your IQ in Old Age
with Professor Lawrence Whalley
Lawrence - We looked at archives of peoples' IQ tests from 1932 and 1947. We used this childhood data to look at lifelong changes in mental ability. These people are now old -from 63 to 84 - so we're getting a spectrum of change.
Chris - What have you found?
Lawrence - We have found that some of the decline in mental ability with age is due to genetic factors. As far as environmental factors are concerned, we found that smoking advances ageing in the brain by one to two years. This is contrary to people who say that smoking is good for them and that it improves their vigilance and attention.
Chris - Why is there damage to the brain?
Lawrence - I think there are two possible reasons that the brain is damaged. Firstly, the efficiency of the lungs is impaired, meaning that less oxygen can get to the brain. Secondly, the oxidative stress caused by smoking might extend further than just the lungs, and affect the brain [leading to directly to damage of nerve cells, and to damage to blood vessels in the brain, affecting blood flow to the brain].
- The Brain-science of Addiction
The Brain-science of Addiction
with Professor Barry Everitt
Chris - Does it matter what age you are when you start being exposed to addictive things?
Barry - This is a really hot area of investigation. Most people start taking drugs when they are really young or adolescent, and our brains are continually maturing and developing until the age of about nineteen, twenty and twenty one. Taking drugs early on, especially hard drugs and alcohol, may have long lasting effects as they interact with the developing brain. It's hard to test, but taking drugs when you are young may mould the brain in ways that make it more susceptible to drugs and less able to live without them. Many fundamental developments occur at this stage in life.
Chris - The common pathway to do with addiction in the brain causes a surge of a chemical that gives people pleasure. Why do we have a part of our brain concerned with letting us become addicted to things?
Barry - That is probably the back to front way of putting it. The first assumption is that during evolution, a mechanism has evolved that mediates the pleasure of life survival activities like eating, drinking and sex. That system is a specific neural pathway in the brain that utilises a certain chemical, in this case dopamine. When you take addictive drugs, it short circuits the system that has evolved to reward natural behaviours. It is not only stimulated by drugs, but is stimulated in a particularly intense and non-adaptive way. This provides the basis for the reinforcing effects of drugs and explains why the drugs are taken voluntarily, at least initially. The real issue is how that might change with time.
Kat - If people can get a high from the things they do, like falling in love or exercising, do these use the same pathways in the brain?
Barry - Not really, no. Things related to everyday activities like exercise quite possibly interact with these pathways at some point but they aren't the same. As Mark Griffiths mentioned, it's about how you define addiction. No-one ever died from not exercising. Compulsion to do certain things (such as exercise) might be a large aspect of addiction but they are not the same thing, although the relationship between them is certainly very interesting.
Chris - Why do the effects of drugs wear off over time, so that people have to take more and more to get the same hit, and then have to take it every day just to feel normal?
Barry - When you constantly bombard systems in the brain, the brain fights back and becomes tolerant. Tolerance then gets caught up in withdrawal symptoms because when you give up the drug, it is even easier to see the evidence of the brain's adaptation.
Gambling Addiction
with Professor Mark Griffiths
Chris - Smoking and cocaine use cause chemical addictions. Are non-chemical addictions like gambling really addictions at all?
Mark - It depends on your definition of an addiction. Personally I think that all addictions consist of 6 components: the first one is salience, which means that it is the single most important thing in that person's life and that they will do it to the neglect of other things in their life. The second thing is mood modification, whereby addiction is used as a consistent method of shifting your mood state; whether to get high or to tranquilise your mood. Thirdly, addicts have withdrawal symptoms, including extreme moodiness, nausea, headaches, sweats and so on. Fourth is increased tolerance, where addicts need more and more over time to reach the same effects. This could involve betting higher sums of money or taking more of a drug. The fifth component is conflict. The addiction becomes so all-engrossing that it harms everything else the person does, including work, school and relationships. Number 6 is relapse. As soon as the person goes back to the activity they are addicted to, they quickly fall back into the cycle.
Some people don't realise they are addicted until the thing they are addicted to is taken away. For example, smoking is not necessarily all-consuming as people can do it at same time as other things. However, if you stick a smoker on a plane for 24 hours, you can often find that it is the only thing they can think about, thus becoming the most important thing in that person's life. The fact people can smoke and drink at the same time as doing something else means that such activities become a bit of a grey area with regards to spotting addiction. Only in the absence of cigarettes and drink does salience become apparent.
Kat - In recent years, there has become a massive explosion of gambling on the internet. Have you noticed this becoming a problem?
Mark - In 1995 when I started looking into the possibility of internet addiction, I passionately believed that I was going to find big problems. Now, although I still passionately believe there are some internet addicts out there, the actual number is very low. There are differences between people who are addicted to the internet and people who are addicted to things on the internet. What I mean by that is that there are gamblers, shoppers, gamers etc who use the internet but are gambling addicts, not internet addicts. However, there are a small group of people who are genuinely addicted to the internet. They like the technology, the anonymous environment and the disinhibited feeling it gives them. This is something you can't do anywhere else but on the internet. People become addicted to the way they can create new personas, meet people in chat rooms and say things they would not be able to say to people face to face. I have met internet users who fulfil my six criteria and genuinely find the internet conflicting with other aspects of their lives.
Chris - I go to the horses now and again, and sometimes use a one-armed bandit and yet never become addicted. What's going on in the brains of people with addiction?
Mark - Addiction is a very complex process. I work within a biopsychosocial model of addiction, which basically means that I think all addictions is the result of a person's biology, their psychological constitution and the environment they were brought up in. Official figures indicate that around 1% of the population have an addiction, which adds up to 350 000 people in the UK. With the new gambling bill that has just been passed, I think the numbers are likely to increase.
Chris - What makes people get into gambling in the first place?
Mark - Getting into gambling is no different to getting into other addictions. It often involves trying to cope with other deficits in life. Gambling, like drugs, has the capacity to give immense highs and buzzes, which is why many people gamble from time to time. I gamble even though I'm a professor of gambling studies! My point is that all these things are perfectly acceptable activities, but for some people, it goes too far and becomes an addiction. Thankfully few people cross this arbitrary line. The triggers are usually idiosyncratic [specific to the individual].
- Is the smoking vaccine safe in conjunction with things like anti-depressants?
Is the smoking vaccine safe in conjunction with things like anti-depressants?
I can't foresee any possible difficulties with antidepressants. We'd like to include this in further trials.
- I'm an ex-smoker. Every so often I get a dream that I'm smoking and think that it's ok. Is that normal?
I'm an ex-smoker. Every so often I get a dream that I'm smoking and think that it's ok. Is that normal?
It's not unusual for people to dream about things that have happened in the past. It's much better to dream about it than actually do it!
- Does the nicotine vaccine stop the cravings to smoke?
Does the nicotine vaccine stop the cravings to smoke?
Probably not. The mechanism works by stopping the effects, and so might actually increase the cravings. The vaccine is probably best used in combination with something that helps with the withdrawal symptoms. However, by stopping the effects, it also helps to break the cycle of reinforcement. Eventually this may lead to people stopping people smoking because it does nothing to help the cravings.
Are fizzy and sweet drinks addictive?
Coca Cola, most other fizzy drinks and cold remedies contain huge amount of caffeine. This is a legal drug that gives you energy and perks you up. This is why taking certain 'flu remedies make you feel more awake and generally much better. These are similar effects to those found when drinking coffee. There are specific receptors in your brain for caffeine. These interact with a part of the brain that uses the reward-chemical dopamine, the same system activated by drugs such as cocaine. Although caffeine and cocaine don't give the same kind of rush effect, both have a common mechanism. It's also worth bearing in mind that tea also contains a lot of caffeine.
- Nicorette gum has helped me to give up smoking. What happens if I get addicted to the gum?! ?
Nicorette gum has helped me to give up smoking. What happens if I get addicted to the gum?! ?
Nicotine gum is useful because it provides a bridge while you are trying to stop. It won't cure your addiction but helps ease the withdrawal symptoms. At the end of the day, the gum doesn't cause damage like smoking does, and so the gum is a much better option. Smoking causes a third of all cancers and the total number of deaths attributable to smoking is 120 000 per year. This is roughly the same as those washed away in the tsunami and is the same as a jumbo jet crashing in this country every day. Smoking does cause lung cancer, but most people don't live long enough to get it: they die of heart disease long before this.
- Do cigarettes suppress appetite?
Do cigarettes suppress appetite?
Indeed, there's quite a lot of evidence that high fat foods have effects on some of the same brain systems as certain addictive drugs. It is also true that cigarettes are anorexic agents - not that long ago cigarettes were prescribed to reduce appetite and assist in weight loss.
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