What I am saying is that every aspect of addiction derives from something physical in the brain, EVEN "rituals". This is simple classical conditioning where scientists observe something called long term potentiation (LTP) in neurons after being conditioned. For example, many organisms, including fruit flies, can learn to associate an odor with a shock and will avoid the odor, even if it is one that had previously been attractive (like a food odor), the next time it is perceived. When one analyzes the neurons, changes have taken place in the part of the brain important for learning.

Nicotine addiction derives from physical changes in neuronal connectivity, receptor expression, and other protein modifications in neurons. These types of changes in neurons also occur to create a memory or are involved in association of certain events with pleasure. For example, some people associate certain activities with receiving "pleasure" from the reward system of the brain because they are smoking while doing this activity and also activating the reward system through a drug. This is associative learning. The neurons that associate these pathways are strengthened such that one "misses" smoking when doing that activity. This is how the brain works and it is completely physical. Actually, ALL activity of the brain is physical: thoughts, feelings, etc. They are all caused by action potentials that are caused by the opening of ion channels and the flow of Na+ ions into cells . Some people believe that psychology is becoming a "folk" subject, like phrenology, and will eventually be replaced by Neuroscience.

What HWI and others, therefore, are terming "psychological" is actually physical as well. Addiction to nicotine (or other drugs) is NOT just about having withdrawal symptoms. That is NOT the only "physical" change. The associations with rewards are ALSO physical changes in neurons and comprise addiction. These drugs profoundly change MANY areas of the brain, including connections between reward and memory and drive. The talk I attended today was about nicotine affecting both GABA neurons (the major inhibitory neurons in the brain) and Glutamatergic neurons (the major excitatory neurons in the brain, often studied in the hippocampus, one of the centers for learning and memory). This is another reason to NOT start smoking to begin with because some of the PHYSICAL changes are NOT reversible and people may always feel the "desire" for some of these drugs because of these neuronal connections, formed through taking drugs. I think that some people may be confused and think that the alterations in muscular output are physical, while changes in the brain that do not lead to muscular output (like learning and memory or associations) are not physical, when both are.


Dekoya,

You do know what smoking can do to an unborn child, right? Or what second hand smoke can do to your children? I actually just got back from a talk about how nicotine affects neurons during development, delaying their growth. This could have profound effects on children later in life and it has been observed that children whose parents smoked not only can DIE before birth, but are slower learners and have behavioral issues, if the baby survives! Here is some important information:

The reasons to quit smoking could fill a book. If you're planning to have a baby or are already pregnant, you have one more very important reason to quit smoking-the health of your unborn child. Consider these facts.

Smoking and Birth Weight

When you smoke, your unborn baby smokes, too. On average, babies of women who smoke weigh less at birth than babies of nonsmokers. And if you smoke a lot during pregnancy-more than a pack a day-the baby's birth weight is likely to be even lower. This is not surprising, since the nicotine in cigarettes causes the baby's blood to be starved of the oxygen needed for healthy growth. Although the baby quickly gains back the lost weight, by age 7 a child of a mother who smoked during pregnancy is still more likely than other children to be shorter in height, slower at reading and lower in "social adjustment" than children of nonsmoking mothers.
Smoking and Infant Mortality

Statistics show that infant mortality-the death of the baby either at birth or through a miscarriage-is 50 percent higher when the mother smokes. That means nonsmokers experience half as many infant mortalities. Children of smokers are also 2½ times more likely to die of sudden infant death syndrome, or crib death. The good news is that if you stop smoking by the fourth month of pregnancy, you can significantly reduce these dangers.

Smoking and Your Health

Parenting is a demanding job. You need to be in peak condition. And you want to be there for your children. People who smoke have higher rates of illness and more serious health problems than nonsmokers. Lung cancer alone kills 30,000 women a year. Stop smoking now, so you'll be able to take care of your children when they need you.

Smoking and Your Family's Health

It's now known that passive smoking-the smoke inhaled by nonsmokers when a smoker is in the room-is unhealthy. This is especially true for children who are particularly sensitive to the problems caused by passive smoking.

The Benefits of Quitting

You can see that your unborn child will benefit from your quitting. This goes for fathers as well as mothers. And the benefits start right away. With time, you-and your children-will be just as healthy as nonsmoking families.

Quitting smoking is not easy, but with help, you can do it. Enroll in a stop-smoking program now. Make it a family project."

Anna