A recent talk I gave (click here), highlighted the fact that other aspects of smoking are very important for addiction to cigarettes. For some people, this isn’t news, especially if you’ve been reading our coverage about the importance of cues for smoking addiction. But that’s not all that makes cigarettes so hard to quit.
Cigarettes, chemicals, and addiction
Thousands of chemicals are released when cigarettes are smoked, including the nicotine we’ve been hearing so much about as well as formaldehyde, benzene, and other nasty things. Some of the chemicals that are released have psychoactive effects, and a few, like acetaldehyde (the chemical that causes hangovers), and a group of monoamine oxidase inhibitors (yes, like old school MAOI antidepressants), apparently increase the effects of nicotine itself greatly, making it far more rewarding, and therefore theoretically addictive, than it would be without them.
The recent paper by a group at Duke University, suggests that there may be aspects of the smoke in cigarettes, even without nicotine, that are themselves rewarding. In the study, researchers gave people the option of taking nicotine by IV or smoking a de-nicotinzed cigarette – Overwhelmingly, participants chose to smoke the nicotine-free cigarettes.
Limitations and conclusions
Now granted, these were regular smokers, which meant that regardless of the effect, the act of smoking was so pre-programmmed for them as a rewarding one that overcoming it just for an experiment is a far-fetched notion. Still, given the hard time I’m having using nicotine as a reward, it seems likely that the other chemicals, as well as the experience of the smoke itself, play a very important role in addiction to cigarettes. Indeed, researchers years ago were very interested in discussing the role off the insula, a brain region important for bodily sensations (possibly involved in cravings and urges).
Another important limitation of this study was the fact that the “de-nicotinized” cigarettes actually had very small amounts of nicotine in them. This little tidbit of information is important because even small, “priming,” doses of a drug can cause very strong effects in terms of drug-seeking and drug-wanting. Maybe in the future there’d be some way of repeating this sort of study with cigarettes that actually contain no nicotine whatsoever.
Rose, J.E., Salley, A., Behm, F.M., Bates, J.E., and Westman, E.C. (2010). Reinforcing effects of nicotine and non-nicotine components of cigarette smoke. Psychopharmacology, 210, 1-12.