Desire and the brain

Dr. Maté cautions that although addiction has some of the features of illness, viewing addiction as a disease or illness, "acquired or inherited, narrows it down to a medical issue. He emphasizes that "we need to avoid the trap of believing that addiction can be reduced to the actions of brain chemicals or nerve circuits or any other kind of neurobiological, psychological or sociological data. A multilevel exploration is necessary because it is impossible to understand addiction from any one perspective, no matter how accurate. Addiction is a complex condition, a complex interaction between human beings and their environment."

    A whole new brain

The following excerpts are from CBC News, "Ancient systems in the brain drive human cravings" (January 2013):

(1) on the brain transmitter systems

Richard Beninger is a behavioural neuroscientist at Queen's University, who recalls that as a student he studied the brain as a collection of parts. "You could see white matter and dark matter and lots of fine detail, right down to the neuron level, but it was all morphology, structure," he said.

"But all of that changed, once scientists began to understand the chemical pathways in the brain. The morphology is still there, but now we know what the transmitter systems are. So we have a whole new brain only in the last 40 years to work with," Beninger said.

(2) on the brain and food addiction

Increasingly scientists also believe food can hijack the brain's reward system. At York University, Professor Caroline Davis is studying the biological basis of food addiction. She says the brain's reward system can be particularly sensitive to highly processed food with combinations of salt, sugar, fat and flavours found nowhere in nature.

"Because they're so palatable, we tend to eat a lot of them and they give us a greater dopamine boost than broccoli does," Davis said. "The things loaded with sugar, loaded with fat, salt, in combination they're very, very hard to resist and there’s evidence that if you eat enough of these foods, in some vulnerable people, they display behaviour that is very similar to the behaviour that we see in other addicts."

When lab rats are given access to sugary food, they binge, and when the sugar is taken away they show physical withdrawal systems that resemble the animal's withdrawal from heroin. Research has shown that dopamine is one of the pathways activated in these sugar-addicted rats.

    Pleasure systems

There are two separate pleasure systems in our brain.

The first, the "appetitive" pleasure system, relates to exciting pleasure, such as when we anticipate or imagine something we desire. The pleasurable feeling we experience is from the release of dopamine, the pleasure-giving neurotransmitter.

The second pleasure system relates to satisfying pleasure. It relates to the pleasure we feel when we have consummated or fulfilled what we've been anticipating or desiring. The release of endorphins makes us feel euphoric.

    Cravings and the brain

Craving is one of the hallmarks of addiction. Cravings are strong memories that are linked to feelings of pleasure and euphoria. Someone with an obsessive compulsive disorder (OCD) persists in ritualized behaviour that is psychologically debilitating and often physically harmful. However the person with OCD has no craving for the behaviour. There are no memories attached to the behaviour that are linked to feelings of pleasure and euphoria. But for the person with an addiction, memory and anticipation create an intense desire for more of the pleasure-giving experience. As Dr. Maté explains, "she doesn't stop the behaviour in spite of its ill effects. She makes promises to herself or others to quit, but despite pain, peril and promises, she keeps relapsing. There are exceptions, of course. Some addicts never recognize the harm their behaviours cause and never form resolutions to end them. They stay in denial and rationalization. Others openly accept the risk, resolving to live and die 'my way.'"

Cravings may occur when the brain becomes tolerant or sensitized to a drug or experience.

    Sensitization, tolerance, dependence

As Norman Doidge explains Chapter 4 of The Brain That Changes Itself, sensitization is different from tolerance. As sensitization develops, less and less of the substance or experience is required for the addict to want it intensely. As tolerance develops, more and more of the substance or experience is required for the pleasant effect to occur. Sensitization leads to increased wanting.

Gabor Maté explains that tolerance is an instance of the addict needing "to use more and more of the same substance or engage in more and more of the same behavour, to get the same rewarding effects." Note also that "although tolerance is a common effect of many addictions, a person does not need to have developed a tolerance to be addicted."

"And then there's physical dependence," he adds. "As defined in medical terms, physical dependence is manifested when a person stops taking a substance and, due to changes in the brain and body, she experiences withdrawal symptoms. Those temporary drug-induced changes form the basis of physical dependence. Although a feature of drug addiction, a person's physical dependence on a substance does not necessarily imply that he is addicted to it... You don't have to be addicted to experience withdrawal--you just have to have been taking a medication for an extended period of time... Withdrawal does not mean you were addicted; for addiction, there also needs to be craving and relapse."

In relation to addiction, Maté explains, dependence means that "the addict comes to depend on the substance or behaviour in order to make himself feel momentarily calmer or more excited or less dissatisfied with his life... Father Sam Portaro, author and former Episcopalian Chaplain to the University of Chicago, said it admirably well in a recent lecture: 'The heart of addiction is dependency, excessive dependency, unhealthy dependency--unhealthy in the sense of unwhole, dependency that disintegrates and destroys.'" In the Realm of Hungry Ghosts (2008)

    Wanting vs. liking

Distinguishing between wanting and liking makes it clear that craving the next fix is not a simple matter of the addict liking the pleasure it gives and avoiding the pain of withdrawal. Doidge reminds us that addicts want and take drugs when there is no prospect of pleasure, and even when they know they don't have enough of the substance for a high, and they will crave more even before they begin to withdraw.

    Do drugs cause addiction?

Gabor Maté emphasizes that "in the cloudy swirl of misleading ideas surrounding public discussion of addiction there's one that that stands out: the misconception that drug taking by itself will lead to addiction--in other words, that the cause of addiction resides in the power of the drug over the human brain." This misconception "obscures the existence of a basic addiction process of which drugs are only one possible object among many... If drugs by themselves could cause addiction, we would not be safe offering narcotics to anyone. Medical evidence has repeatedly shown that opioids prescribed for cancer pain, even for long periods of time, do not lead to addiction except in a minority of susceptible people."

He argues that "we can never understand addiction if we look for its sources exclusively in the actions of chemicals, no matter how powerful they are... It is true that some people will become hooked on substances after only a few times of using, with potentially tragic consequences, but to understand why, we have to know what about those individuals makes them vulnerable to addiction. Mere exposure to a stimulant or narcotic or to any other mood-altering chemical does not make a person susceptible. If she becomes an addict, it's because she's already at risk" (In the Realm of Hungry Ghosts).

    Addiction, context, and behavioural principles