One of them is that we all have an internal struggle going on between parts of the brain that represent desire (limbic system) and rational thinking (prefrontal cortex or PFC). So these two main structures in the brain are locked in a rather constant conflict over the control over your behavior.
The amygdala and the rest of the limbic brain will make instinctual and habitual behavior dominate if activated by situations that seem “biological relevant” because they are dangerous (suvival) or sexually interesting (procration). Your rational mind supported by the PFC is active when you direct, plan, execute your plans or when you monitor and modify your behavior according to long term goals. These two systems have very different biological origins and they make very different contributions to success and survival. The balance that you have between them is crucial in almost any situation. But let us take a look at each on their own terms.
Limbic structures structured around the amygdala (two almond shaped structures on each side of the top of the brain stem and just under the corpus callosum.
As you are swayed by amygdala activation you become more focused on here-and-now benefits and less focused on long term consequences. This change benefits survival as you need to secure survival now, not later. The basic obvious fact is that you can not correct for lacking survival later, even if your long term plans are fine, if you are six feet under when you are supposed to do so. Survival delayed is survival denied.
The limbic system is rational only in the sense that is is born out of a rational process: The survival and procreation of all the individuals in your evolutionary past, your biological forefathers. The process of evolution has sorted between the quick and the dead and your brain equipment and inherent tendencies have been proven through millions of year of lived experience. The influence of the amygdala is rational in the context of survival, but not in the context of personal experience or situation.
So it would be misguided to cast the influence of the amygdala as “evil” or “regressive”. But it does represent a challenge when you want to further personal projects and long term plans. With your advanced brain comes a set of opportunities and a set of challenges. It is up to you to negotiate a path towards a fulfilling life and this is done most successfully when you understand the forces that will sidetrack you along the way.
The PFC or prefrontal cortex
It used to be “largely decorative” as life in a natural habitat was most successfully managed by way of instinctive behavior. Two things have changed this situation:
1) We live in a world that we are poorly equiped to react to by way of instinct.
The dangers that have shaped our instinctual reactions are now no longer significant causes of death. In most cases they are rare and exotic phenomena that we most often encounter in the comfortable seats of our local cinema. At the same time there is a quite a bit of substitution going on, so that fear of ridicule now inhabits the structures that used to host fear of expulsion or banishment from tribe or clan. While the dangers have greatly diminished, there is a constant recalibration going on that makes sure that reactions to risk and avoidance of dangers are still a huge factor in determining your everyday behavior.
2) The stability and safety of modern day civilization favors long term planing and execution. Because our civilized world is a lot more predictable planing and execution of long term goals are a lot more likely for a modern day person. If your average life expectancy is hovering around 35 years it does not make much sense to spend 20 of those years on education.
The basic assumption is that addiction is a case of the limbic brain overwhelming the PFC and the self control asserted by the PFC. This was traditionally seen as a case of the reward centers being too active for the PFC to handle. The alternative view that the PFC is just too weak in general regardless of the reward centers is more in vouge lately. There is nothing to suggest that both views are not essentially correct, either for different people at different times or indeed at the same time in the same person. Both will have the same basic result: That instinctive short term behavior dominates which for some people means drug taking.
But what the medical model also claims is that the weakness of the PFC and the consequent weak self control is an effect of drug taking. Or that the over activity of the reward centers and the consequent strong desire it entails are effects of taking drugs. Or indeed that both are effects of taking drugs. As this a major point of contention we will have to argue this a bit more in detail on the following pages.