Pill to make smokers forget their craving
A blood pressure pill might help people quit smoking.
Researchers believe that the beta blocker drug works on certain brain chemicals and effectively deletes some of the memories associated with the habit.
It is these memories which help drive the craving and lead to thousands of would-be quitters relapsing.
There are an estimated 10 million smokers in the UK — around a quarter of men smoke, which is just slightly more than the number of women who do.
While 70 percent try to give up each year, only 5 to 15% manage to do so for more than 12 months.
One of the most popular aids for quitting smoking is nicotine replacement therapy (NRT), which comes in the form of gum, patches, lozenges or inhalers.
NRT works by releasing nicotine steadily into the bloodstream at much lower levels than in a cigarette, and without the tar, carbon monoxide and other poisonous chemicals found in tobacco smoke.
However, while NRT tackles the physically addictive nature of smoking, it might not tackle the desire or craving to smoke.
The new treatment, known as memory reconsolidation blockade, targets this craving and could be used in conjunction with nicotine replacement therapy.
Smoking, along with many drug addictions, triggers an increased release of the brain chemical dopamine, a neurotransmitter that is involved in controlling movement, emotional response, the ability to experience pleasure and pain, and short-term memory.
One of the latest theories on addiction is that this high level of dopamine tricks the brain into thinking the addictive substance is important to it.
When the memory of that addictive substance is triggered - by an environmental cue such as holding a glass of wine or drinking coffee - this produces a positive emotional response.
This, in turn, leads to a craving for the substance.
Scientists have for some time been investigating the idea that blood pressure pills – beta blockers - can affect aspects of memory.
According to a University of Maryland report, one of the potential side-effects of beta blockers is memory loss.
One theory is that some beta blockers interfere with the chemical norepinephrine, which is involved in the brain’s natural ‘filing system’.
Every time we recall a memory it is changed a little, which means it then has to be ‘re-filed’. Beta blocker drugs somehow interfere with this process, although not obliterating the memory itself, just the emotional response it provokes.
Previous studies on animals have shown that those given injections of a beta blocker were less likely to recall being afraid of certain things.
In the trial at Massachusetts General Hospital, smokers who have smoked at least ten cigarettes a day for the past three months are being given the beta blocker propranolol.
The study, which involves 50 smokers, includes a smoking cessation phase, where the men and women will be given nicotine patches, and a relapse prevention phase where they will be assigned to receive either propranolol or a placebo once a week for six weeks.
During this time, they will regularly be exposed to their own personal environmental smoking triggers.
‘It is a very exciting concept,’ says Dr Paul Kenny of the Scripps Research Institute, a leading researcher in the field. ‘The theory is that it blocks or erases memories associated with smoking.
‘There is much incentive to discover and develop novel and efficient therapies for the treatment of tobacco addiction.’
Dr Ken Checinski, consultant psychiatrist and senior lecturer in addictive behaviour at St George’s, University of London, said: ‘It is always exciting to have novel variants of inducing behaviour change.
‘This is a promising approach and we should watch for the results with interest.
‘It will not be a “magic bullet”, as smoking behaviours have multiple causes.
‘However, if smokers with cue-related craving are targeted, this might be a particularly powerful method.’
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