Thursday, January 28, 2016

Dopamine: “The Anticipation Molecule”


by Peter R. Coleman, MD

For a long time, it has been known that dopamine is the pleasure molecule. After all, it is common knowledge that a large amount of dopamine is released in the nucleus accumbens area of the brain when we do pleasurable things - like eat food and have sex.  When the dopamine is released, we experience a strong sensation of pleasure and, of course, we are likely to want to repeat that experience.  We also know that all addictive drugs release massive amounts of dopamine in the nucleus accumbens - way more dopamine than we humans were ever meant to experience.  This heightened pleasure sensation is the biggest reason why people use addictive drugs.
 
But now, more light is being shed on just how complex are our brains and how different parts of the brain interact. Scientists are now also calling dopamine “the anticipation molecule” because it has been shown that dopamine is also released in large amounts when we anticipate a pleasurable experience.  We actually release dopamine in the nucleus accumbens and get a sensation of pleasure by just thinking about having one of these experiences. Actually, just thinking about having a pleasurable experience is not quite enough to release a lot of dopamine. The large amount of dopamine is released when two things happen - we both think about the pleasurable experience and there is a realistic opportunity that we will be able to have the pleasurable experience - true anticipation.
 
We can all relate to this and know that this is true. I’ll stick with the food example.  Let’s say we are quite hungry and someone brings out a plate of warm chocolate chip cookies.  We are suddenly presented with the opportunity to eat one of our favorite comfort foods.  In this situation our brains will actually release a small amount of dopamine and we will experience a thought - “maybe I should have one cookie”.  We start to process this situation and think about the different possibilities. We could refuse the temptation and not have the cookie, or maybe we think that we could have just one.   Our thoughts about the cookies begin to become a little more like a desire.  We analyze the pros and the cons.   Our thoughts are becoming more like a craving.   Our mind starts to swing towards making the decision that one cookie wouldn’t be so bad, and “What the heck - I deserve it”, or “Why not - I can go to the gym later”. As we allow these thoughts to build, we start to imagine what the cookie will taste like and how it will be amazingly delicious.  Our old memories kick in.  At this point, our pleasure center is releasing so much dopamine, we are getting very excited and we can’t wait to eat that cookie. We know how good it is going to be! We feel great!
 
And then, we bite into the cookie, and it happens - the cookie wasn’t that good.  It was an okay cookie, but it was not nearly as good as we had imagined. “The cookie lied to me!”  “Now I am going to get fat, and for what - a lousy cookie that didn’t even taste that good”.  It is amazing to know we actually got more dopamine from anticipating the cookie than we received from the cookie itself.
 
Drug addiction is just the same.  Even patients who are physically addicted to opiates have to go through all sorts of mind games each time they decide whether to use or not. They all know using drugs is bad, horrible, and they should stop.  But, once they have the opportunity to use, the dopamine kicks in so strongly that not using becomes almost impossible. And, frequently, it is just like the unsatisfying cookie - it wasn’t that satisfying.  Addiction is cruel for both the addicts and everyone around them.

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