The relationship between addiction and dopamine

You see the coffee maker … and even if it hasn’t crossed your mind, you can’t help but have a cup of coffee. When does something become an addiction? What is the relationship between addiction and dopamine? Do we dearly like what is addicting?

The relationship between dopamine and addiction can be clearly seen in this picture.
The relationship between dopamine and addiction can be clearly seen in this picture.

It was believed that dopamine powers both desire and pleasure. Additionally, there appeared to be compelling evidence that dopamine was essential to pleasure. An experiment was carried out on this. Rats love things that are sugary. Kent Berridge found another way to study the link between dopamine and pleasure. After removing dopamine from the rats’ brains, he fed them a sugary substance. And to our surprise, the rats still liked the taste. The pleasure was still there!

In another experiment in his laboratory, dopamine levels were increased in rats. This caused a large increase in food, but without an apparent increase in taste. How can a scientist tell if a rodent is having fun? It turns out that rats have facial expressions similar to humans. When they eat a sweet substance, they lick their lips; If it’s bitter, they open their mouths and shake their heads.

So, what’s up? Why do rats still like food that they don’t seem to want anymore?

Kent Berridge had a hypothesis. Could it be possible that wanting something and liking it corresponded to different systems of the brain? And could it be that dopamine wasn’t affecting the taste, that it was just about wanting this thing?

The scientific community remained skeptical for many years. But now the theory has been widely accepted. Dopamine increases temptation. When I go downstairs in the morning and see my coffee pot, it’s the dopamine that drives me to make a cup. Dopamine increases the urge to eat when hungry and makes the smoker crave a cigarette.

The most surprising evidence that the dopamine system triggers wanting and not-loving comes from another experiment. Kent Berridge placed a small metal rod in the rat’s cage that caused a small electric shock if touched. A normal rat learns to stay away from the bar after a touch or two. By activating the rat’s dopamine system, Berridge was able to immerse the rodent in the rod.

Experiments with rats and sugar help to understand addictions
Experiments with rats and sugar help to understand addictions

The relationship between addiction and dopamine would be clearer this way. Kent Berridge changed the scientific understanding of desire and motivation in humans. He claims that wanting is more fundamental than liking. Ultimately, it doesn’t matter to the maintenance of our genes whether we like sex or food. Much more important is when we want to have sex and when we are looking for food.

The most important implication of the distinction between wanting and liking is the perception of addiction, be it to drugs, alcohol, gambling and maybe even food.

Sensitive addicts

For the addict, want is separate from taste. The dopamine system learns that certain signals, such as seeing a coffee pot, can bring rewards.

Somehow, the addict’s dopamine system becomes sensitized in a way that is not fully understood. The will never goes away and is triggered by numerous signs. Drug addicts may feel the urge to use drugs delivered through a syringe or spoon, even when they are at a party or on a street corner. This makes drug addicts extremely prone to relapse. They want to return to drugs, even if the drugs give them little or no pleasure.

The task of the researchers now is to find out whether they can reverse this sensitization in rats and, hopefully, in humans as well.

And you, do you have an addiction that you now understand better?

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