One of the most common resolutions people make is to quit smoking Nikotinoff. Smoking is an addiction and as such, it can be very difficult to be successful. Smokers will tell you that there are very powerful cues that will get them to smoke. For example, having coffee or a glass of wine can be the kind of environmental cues that stimulate the desire to have a cigarette for smokers. Watching other smokers may also cause a craving. These kinds of cues can make it difficult to quit or to avoid a relapse in those who have quit.
Newer imaging of the brain with functional magnetic resonance imaging (or fMRI) and positron emission tomography (or PET) scanning give us new insight into what happens in the brain of a smoker. There are certain regions in the brain that are now known to be associated with cue driven smoking. These include:
- prefrontal cortex, which drives attention
- amygdala, which drives emotion
- ventral tegmental area, which drives reward
- striatum, which drives motivation
This week, in the Archives of General Psychiatry, are two studies looking at two smoking cessation medications. The first, bupropion, was originally marketed as an anti-depressant. It is known to reduce cravings in response to cues. In the bupropion study, the participants had fMRI at the beginning of the study and then at the end of an 8-week treatment period. What they found was that when shown 45-second videos with smoking cues or neutral cues, those who were treated had less response to smoking cues than those who had a placebo. Their scans, as well, showed reduced activation in those areas of the brain that are now known to be associated with cravings. The reports of cravings matched the fMRI images- those who showed reduced activation also had fewer cravings.
The second study looked at varenicline, which reduces withdrawal symptoms and the reinforcement received from nicotine while smoking. The brains of smokers were imaged before and after the medication while at rest and while viewing video clips of smoking and non-smoking cues. Smokers were still smoking during the medication regimen to allow for the study of the medication effects on reaction to cues independent of withdrawal, which is known to affect brain reactivity as well. Again, those who were medicated as compared to the placebo group showed a change in brain activity and self-reported cravings.
The two findings went hand in hand. The areas of the brain that blunts the response to smoking cues — the ventral striatum and medial orbitofrontal cortex — were activated by the medication and as a result, there was less of a response to a smoking cue. Even in the resting condition, those medicated showed increased activity in a region of the brain that inhibits behaviour that predicts reward-the lateral orbitofrontal cortex. As a result, when there was a smoking cue, there was no desire to reward that cue by smoking. This increased activation in this particular area- shows how the medication works to reduce the effects of smoking cues on both the brain and craving.
These two studies are important in showing how the medications work in impacting cue-induced smoking and withdrawal-induced cravings. If you are ready to quit smoking, speak to your doctor about these two important treatment options.