How does an addiction affect the brain?

Addictions are phenomena whose root has a neurological basis. Studies on this issue agree that the brain is the axis around which the clinical expression of the same orbits, so it is concluded that behind it always lies an organic nuance.

However, drug addicts have traditionally suffered from social ostracism and rejection, realizing that their problem was the result of personal weakness or even simple evil. That is why they have been singled out and blamed for their plight on countless occasions, while denying any option of reinstatement.

Today, we know that consumption begins with an unfortunate decision, motivated and supported by personal or social circumstances; but that in its “maintenance” various forces participate with which it is not easy to struggle (anatomical / functional changes in neurology itself).

In this article, we will explore how consumption affects the brain and behavior, so that they can thoroughly detail its causes and consequences. It is from there that we can better understand the “how and why” of a health problem of enormous human and social importance. The goal is to answer this question: How does addiction affect the brain?

    What is an addiction?

    The word “addiction” comes from classical languages, and more precisely from the Latin term “addictio”, which literally translates to “slavery”. From the same origin, we therefore deduce that those who fall into the clutches are deprived of the freedom to think and act freely.

    Drug dependence is a chronic disease caused by structural and functional changes in brain tissue, Etiology has two possible sources of identical contribution: genetics and learning (biology can explain 40% -60% of the variance according to comparative studies carried out with monozygotic twins).

    There are a number of symptoms that allow accurate detection of addiction: urge (an overwhelming desire to consume where it was done), tolerance (need to use an ever increasing dose of a drug to feel the pain). same effect as in its beginning), withdrawal syndrome (severe discomfort when stopping the administration of the substance), loss of control (excessive time to consume and recover from its effects) i difficulty quitting the habit despite its negative impact on everyday life.

    All these phenomena can be explained in a simple way by resorting to changes in the brain systems involved. Let’s look at this in detail.

    The effects of addiction on the brain

    All of the behavioral / attitudinal symptoms that are evident in people with addiction have a clear correlate in their brains. And this is it addiction has the ability to promote the neural adaptations underlying the cognitive and affective experience of those who present it, and who should never be perceived or interpreted as a “plaintive” or “harmful” attitude. Such a judgment is unfair and imprecise, reductionist in every way, and not at all adjusted to current knowledge of the matter.

    Let’s look at the addictive process from its very beginnings, and how in all its phases we can find a neurological mechanism that reflects it.

    1. Beginning: the hedonic principle

    Pleasure is one of the essential engines of human behavior. It is the spring which makes explode the desire to approach a stimulus in the environment, or to repeat a particular behavior adaptive to life. Among them, there is sex, food or play; for which a common brain mechanism is known which favors their research and realization. More precisely, in the deepest abysses of this organ can be found a neural network “activated” when we experience a pleasant event (Or we subjectively perceive it as positive): the reward system.

    Anything that people can do that generates pleasure inexcusably passes through their stimulation. When we eat what we love the most, we are making love or simply sharing happy moments with a loved one; this set of structures is responsible for feeling positive emotions that they encourage us to repeat these behaviors and / or activities on successive occasions. For these cases, a discrete increase in regional production of the neurotransmitter dopamine would be observed, although within the healthy physiological threshold.

    However, when we observe in detail the functioning of the brain when using a substance (one of them), we see that in this neuronal complex formed by the nucleus accumbens, the ventral tegmental zone and its projections specific to the prefrontal cortex) a There is a “massive” discharge of said neurotransmitter (dopamine). This activation is similar to that shown in natural enhancers, but with one exception: the amount secreted is between two and ten times higher than that motivated by them, as well as much more immediate and clear in the experience.

    The result of such a process is that the person feels intoxicated with a great sensation of pleasure right after consuming the drug. (Although the time it takes to get in depends on the chemical properties of it and the route chosen for its administration), so much so that it exceeds that of any activator available in the natural environment. The main problem with all of this is that over time what was rewarding would cease to be so; replacing himself with the drugs on which he depends. The result is usually the loss of very important relationships and the deterioration of professional or academic responsibilities.

      2. Maintenance: learning

      Hyperactivation of the reward system and the associated pleasure experience is just the first step towards chemical addiction, but not the only one.. Otherwise, anyone who consumes a substance would become addicted to it from the moment it entered the body, which is not the case. This process takes time and depends on the learning network that the individual weaves with the stimuli and sensations associated with the objective consumption situation. So, there is a psychological component that would help build addiction, alongside neurological and chemical components.

      Dopamine, the neurotransmitter that coordinates the pleasure response, also has a role in memory and learning among its many functions.. This is especially true in conjunction with glutamate, which helps to trace the functional relationship between drug use and its consequences or environmental keys. This is how the person will not only feel pleasure after using the substance, but proceed to make a complete map of the environmental and experiential topography of the same moment (what is happening and what they are feeling) , which will help him understand their experience and orient himself when they aspire again to these sensations (by looking for how to acquire and administer the drug).

      This neurological process forges a cause-and-effect relationship that forms the basis of addictions, and is fundamental to explaining the link between subjective sensations and their link with the drug used, which will later articulate a motor behavior aimed at their research and consumption ( addiction). As the person repeats the association, its intensity will be gradually strengthened (closer connections between the nucleus accumbens and the prefrontal cortex). These brain changes ultimately result in the distortion of the original pleasure, which it would become an urgent and extremely invasive necessity.

      At this point, the person has often lost motivation for what was once the very center of their life (from social relationships to personal projects), and focuses their efforts only on consumption. To all this contributes the fact that the structures of the primitive brain are coordinated with those of more recent appearance (neocortex), forming a pernicious alliance which deteriorates much of what happened in the past.

      3. Abandonment: tolerance and desire

      The brain changes associated with consumption on the reward system involve an artificial modification of its natural function, so that the organ tries to adapt to it by generating a compensation that reverses it (with the ultimate goal of recovery homeostasis). So when addiction is finally established, it charges an inevitable toll: whenever the drug causes minor effects, the person is forced to increase the dose perceive sensations comparable to that of the beginning (tolerance).

      This attenuating effect can be explained as follows: the substance promotes an increase in “dopaminergic availability” in the fissure of the synapses of the reward system, saturating the receptors for it located in the region. In order to correct this functional aberration, a “downward” regulation of these would be given, the result would be the reduction of their presence and the psychotropic effect on the way they feel and think. The substance would thus lose its impact on interior life, and would continue to wage a battle between the individual (which would increase consumption) and his brain (which would compensate for all this “effort”).

      At this point in the process, the subject (who is already deeply affected by the neurological changes in the addiction process) would experience a compulsive search for the substance that would displace everything else. When it was not available, intense physical / emotional discomfort erupted, called withdrawal syndrome (and opposing the effect the drug causes during poisoning). All of this can be even more difficult when the addict does not make changes in the dynamics of their daily life, and continues to live with the same stimuli with which they did when they were in the active phase of consumption. .

      These difficulties result from the participation of two very specific brain structures: the hippocampus and the amygdala. While the first of these allows for the creation of new content in memory, the second is responsible for processing the emotions that arise from our experiences. When merged, they facilitate the craving, that is, an overwhelming desire for consumption when exposed to the environmental keys associated with it. This phenomenon would be the result of the addictive story, and could be easily explained by classical conditioning (Syringes in injected heroin users, or the mere presence of accompanying persons during the acute effect, for example)

      Conclusions: a complex process

      The process by which an addiction is modeled is usually slow and insidious. In the first months or years, its use is based on the pleasant sensations that are secondary to it (reward system), but which soon give way to a reduction in its effects and an impossible battle to relive them (as a result of neuroadaptation) in which biology eventually prevails. Such a process leads to a loss of motivation for all that was nice, With a gradual withdrawal from social life and / or from one’s own responsibilities or hobbies.

      When this happens (through the network of connections between the nucleus accumbens and the prefrontal cortex), the person may try to abandon the cycle. To do this, he must deal with the general deterioration of his life, as well as the urges to consume when placed near discriminatory stimuli (linked to his personal experience of addiction). It’s the latter phenomenon that triggers the craving, one of the reasons relapses or slips are most common. Its effects are due to the action of the hippocampus and the amygdala.

      In short, addiction should never be explained by referring only to willpower, as underlying neural dimensions are found that need to be addressed. The stigma and rejection that many people face when trying to recover from this problem is a chasm in the flow of their motivation to live full and happy lives again.

      Bibliographical references:

      • Marco, D. (2013). The brain addicted. Frontiers in Psychiatry / Frontiers Research Foundation, 4, 40.
      • Volkow, N., Wang, G. and Fowler, J. and Tomasi, D. (2011). Drug addiction circuits in the human brain. Annual review of pharmacology and toxicology, 52, 321-336.

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