How the brain can transform us from simple pleasure to addiction

The sight of a square of chocolate or, more generally, of a candy causes in some people the desire, even an irresistible urge to consume it. This phenomenon is explained, in part, by the activation of the brain’s reward circuit.

What is happening in our brain and how does the slip into addiction happen?

The mechanisms of pleasure

The ventral tegmental area and the nucleus accumbens are two regions involved in the reward circuit © Pancrat / Wikimedia

The first time we tasted a square of chocolate, the regions of the brain involved in the reward system (mainly the ventral tegmental area and the nucleus accumbens) were activated. This system, which we share with many mammals, aims to maintain our general balance, also called “homeostasis”. It prompts us to engage in activities that are essential for the proper functioning of our body, such as eating or sleeping.

Activation of the reward circuit causes the eventual release of dopamine, the chemical messenger of pleasure. This dopamine release helps to memorize the pleasant stimulus. This is what leads us to repeat behavior that gives us pleasure. Let’s talk about positive reinforcement: I eat a square of chocolate, I enjoy it, my brain memorizes it. The next few times, the reward system activates immediately after seeing the chocolate, even before you put it in your mouth. When I see it, I want to eat it again: I am “conditioned”.

In addition to the archaic reward circuit (I’m hungry, I eat), three other brain circuits are activated when natural rewards: the memory and learning circuit, the motivation circuit (which affects (a person’s commitment to a certain activity) and the control circuit, which makes it possible to respond adequately to social situations.

If the pleasure matches the experience of the reward, then the expectation of that reward probably corresponds to the desire. But we have to push ourselves to the satisfaction of pleasure to maintain positive reinforcement.

Furthermore, humans are not only motivated by their appetite – they are also sensitive to more complex stimuli, such as art or music. It has thus been shown that contemplating a painting or listening to a piece of music, whatever the style, can also stimulate the reward circuit. These stimuli are less innate, because they are not very essential for our survival, they are more sensitive to learning.

When the system gets carried away: from pleasure to addiction

The reward circuit was discovered in the 1950s by James Olds, an American psychologist and neuroscientist, and Peter Milner, a Canadian neuroscientist. The two researchers had implanted electrodes in the nucleus accumbens of a rat’s brain. By pressing a lever, the rat itself could stimulate the region of its brain involved in the reward circuit. Result: the mouse stimulates itself all the time, without even taking the time to eat.

In other words, the direct stimulation of this circuit was so powerful that it became counterproductive, as the animal had forgotten its basic needs. It is on this principle that drugs work, whether they are legal (tobacco, alcohol) or illicit (cocaine, opioids such as heroin …), or even certain behaviors (gambling and money …).

In the beginning, these activities are obviously fun. But then, as the behavior repeats itself, the various brain circuits involved in these behaviors will change.

In addictions, they are out of sync: the reward and memory learning circuits work by themselves, while the motivation and control circuits work in isolation, each at their own angle in some sense. This desynchronization of the brain circuits results in a loss of motivation and control and in the search for immediate reward, learned and recorded through repetition.

Find your good pleasure

To avoid falling into the trap of addiction while continuing to have fun every day, several levers are at our disposal.

When it comes to food, sugars are a powerful stimulator of the reward system, so they should be consumed moderately. The idea is to educate our reward system by sensitizing it to other stimuli: varieties, colors, aromas, flavors… In short, to all those pleasures that can replace the pleasure of sugar. And let’s not forget that eating is also sharing, with family or friends, which increases the pleasure tenfold.

Physical activity is also a source of pleasure that is beneficial for our health. When we play sports, especially when we run, our brain releases cannabinoids and endorphins, molecules that are a source of perceived well-being. However, this pleasure is not immediate: it appears after a certain delay, usually 20 to 30 minutes.

After sport, take a rest. Sleeping is for many a small pleasure that costs nothing. But can we sleep as much as we want without risk to our health? There really isn’t a proven maximum amount of “toxic” sleep. However, long sleep times of over 9 hours are associated with chronic conditions such as diabetes. Obesity has also been linked to the need for excessive sleep or non-restful sleep. It is generally believed that the average ideal sleep duration is between 7 hours and 8 hours per night.

Another source of pleasure not to be overlooked: sexuality. Mainly because it is also a good marker of health status: for example, regular sexual activity is predictive of an increase in survival after a myocardial infarction.

In our connected society, screens have become an essential source of pleasure. Should we limit its use? Here, too, the important thing is to remain measured. We know that screens are not without risks for the most vulnerable children and adolescents. A sedentary lifestyle, being overweight, oppositional behaviors, sleep disturbances or “zapping” thinking are particularly threatening. One must be especially careful with “multitasking” followers, who use multiple screens at the same time and often have a significant, albeit variable, daily viewing time.

On the contrary, the pleasures of the mind such as art or music must be experienced without moderation: a study of British Journal of Psychiatry showed in particular that regular cultural visits are associated with a 30% reduction in depression and even a 50% reduction when they occur once a month or more.

This analysis was written by Boris Hansel, physician, university professor (Faculty of Health, University of Paris) and Laurent Karila, professor of addiction and psychiatry (Paris-Saclay University). The original article was posted on the website of The conversation.