While driving in my car a week or so ago, I heard a fascinating interview on NPR (National Public Radio) of David Linden about his new book: The Compass of Pleasure: Why Some Things Feel So Good. Linden is a professor of neuroscience at the Johns Hopkins University School of Medicine and the chief editor of the Journal of Neurophysiology.
What does it really mean for the brain to experience pleasure? That’s the question neuro-scientist David Linden asks in his new book The Compass of Pleasure: How Our Brains Make Fatty Foods, Orgasm, Exercise, Marijuana, Generosity, Vodka, Learning, and Gambling Feel So Good. In it, he traces the origins of pleasure in the human brain and how and why we become addicted to certain food, chemicals and behaviors.
When Linden spoke with Fresh Air‘s Terry Gross, he explained that the scientific definition of addiction is actually rooted in the brain’s inability to experience pleasure. I urge you to listen to David Linden’s interview and read the transcript. I learned so much about the pleasure circuitry of the brain, and how simple ‘likes’ become full blown addictions.
Here are some thought-provoking excerpts from the interview:
In reference to addiction: we now can better understand addiction from a brain neuroscience perspective.
•While most people are able to achieve a certain degree of pleasure with only moderate indulgence, those with blunted dopamine systems (addicts) are driven to overdo it. Linden explains, “In order to get to that same set point of pleasure that others would get to easily — maybe with two drinks at the bar and a laugh with friends —(an addict/alcoholic) . . . needs six drinks at the bar to get the same thing.”
•Drug (or any kind of addictive substance/behavior) addicts are not motivated to ‘use’ because they get more pleasure – but because they get less pleasure; their sense of pleasure/relief is blunted; their dopamine center is defective to an extent – and is not the same as ‘normies’. In order to experience the same level of pleasure as ‘normies’, they need more; and they build a tolerance level more quickly. They were born this way; just as a diabetic was born not being to handle normal sugar loads.
Linden explained that the scientific definition of addiction is actually rooted in the brain’s inability to experience pleasure. Liking becomes wanting which becomes needing, just to function, to not experience feeling physically ill, to be able to face the day like a more normal person.
“What I’m seeking here in The Compass of Pleasure is a different type of understanding — one less nuanced, perhaps, but more fundamental: a cross-cultural biological explanation. In this book I will argue that most experiences in our lives that we find transcendent — whether illicit vices or socially sanctioned ritual and social practices as diverse as exercise, meditative prayer, or even charitable giving — activate an anatomically and biochemically defined pleasure circuit in the brain. Shopping, orgasm, learning, highly caloric foods, gambling, prayer, dancing ’til you drop, and playing on the Internet: they all evoke neural signals that converge on a small group of interconnected brain areas called the medial forebrain pleasure circuit. It is in these tiny clumps of neurons that human pleasure is felt. This intrinsic pleasure circuitry can also be co-opted by artificial activators like cocaine or nicotine or heroin or alcohol. Evolution has, in effect, hardwired us to catch a pleasure buzz from a wide variety of experiences from crack to cannabis, from meditation to masturbation, from Bordeaux to beef.”
I struggle a bit with the disease model of addiction. I keep looking for what it was that caused my daughter, Hayley, to become a heroin addict at age 31. Did I, as her mother and we, as her parents, not give her enough of something – or too much of something else? What signs along the way did we miss as she was growing up? Did the trauma of her father’s and my divorce when she was 17 contribute to her serious drug addiction? Or was it a gradual building of life stress factors that culminated in the ‘choice’ to smoke crack cocaine or inject heroin in to her veins? Was it inevitable – and she was genetically predisposed to addictive behavior, as evidenced by her eating disorder at age 20, smoking, and gradual onset of substance abuse?
Linden goes on to say in his interview:
•Any one of us could be an addict at any time. Addiction is not fundamentally a moral failing — it’s not a disease of weak-willed losers. Understanding the biology of the pleasure circuit helps us better understand and treat addiction, Linden says. It is important to realize that our pleasure circuits are the result of a combination of genetics, stress and life experience, beginning as early as in the womb.
I found this next tidbit rather surprising, as did my daughter, a smoker (she’s trying to quit – and has gone for up to 30 days without smoking) and recovering heroin addict:
•30 % of those who first inject heroin, become addicted, whereas 80% of those who start smoking become addicted to nicotine. With heroin, there is a large immediate reward – that will satiate the user for up to 12 hours, depending on the dose. The”high” of heroin is considered to be “intermittent” because there is usually a period of several hours between doses – similar to eating a big steak and being sated until the next meal.
However, nicotine is actually more addictive due to the use process. With smoking, there are small reliable rewards that are more constant – liking cutting up a steak into 200 bite-sized pieces. There is almost a constant infusion of nicotine in to the system which creates a more addictive type of learning.
And here, again, is what seems to be a partial answer to my question of how/why my daughter became a heroin addict:
Addiction may be ~ 40% genetic involving a defect in brain chemistry; but the rest is life experience and most importantly stress. “There are variants in genes that turn down the function of dopamine signaling within the pleasure circuit,” Linden explains. For people who carry these gene variants, their muted dopamine systems lead to blunted pleasure circuits, which in turn affects their pleasure-seeking activities”, he says.
Now there is a biological explanation for addiction, which can have profound implications for addicts trying to stay clean; stress often is THE determining factor for use and relapse. However, behavioral strategies to reduce stress, such as those listed below, can be quite effective in preventing relapse:
–exercise; pleasurable physical activities, like playing with or even petting a pet
–support groups and a structured recovery program, like AA
This is all very interesting – and terrifying. Will my daughter ever be able to deal with the ‘normal’ stresses of life – the peaks and valleys of work, personal relationships, health issues – of LIFE?
Unfortunately, with addiction, there are permanent physiological changes in neurons of the pleasure center; the brain has been rewired and is forever changed, which means that an addict will always be an addict and will need to deliberately work at staying sober.
Linden maintains that “Addiction is not fundamentally a moral failing — it’s not a disease of weak-willed losers. When you look at the biology, the only model of addiction that makes sense is a disease-based model, and the only attitude towards addicts that makes sense is one of compassion.”
Now, with new developments in the field of neuroscience and new knowledge about the role brain chemistry plays in the disease of addiction, will we, as a society, be able to change our attitudes about drug addicts – and convert the stigma, guilt, blame, and shame to compassion? Shouldn’t our country adopt policies based on the public health aspect of drug addiction – and effective treatment/support programs for addicts versus our current more punitive approach? Proper/effective treatment of drug addiction and alcoholism should be declared one of our most acute and chronic public health issues with resources appropriated accordingly. Ultimately, our country could be saving billions of dollars now dedicated to law enforcement, legal/court costs, incarceration, and the social/health services and issues funneled towards drug addicts.
I don’t really know how we can accomplish this and shift the culture’s paradigm from punishment to treatment of drug addiction. It’s not a simple ‘fix’, obviously. And with the increasing numbers of drug addicts, who may have children themselves, we potentially face a growing pool of genetically pre-disposed people to addiction, draining our educational, legal, health care, social services systems and work force.
What are your thoughts on how neuroscience is changing our view of and approach to dealing with drug addiction – not only from a personal perspective (as the parent of a drug addict/alcoholic) but also as a citizen of this country, with its limited financial resources and global priorities?