Good Thinking

Ideas that influence the way we think.

The Myth and Reality of Free Will: The Case of Addiction

There are clues that the person is at risk of losing his autonomy, his free will, and even his very life, to the power of addiction. Read More

Great article, thank you. To

Great article, thank you.

To look at my 32 yr old son you'd never know he was a high functioning heroin addict. He just looks like a normal IT guy in his glasses, khaki pants and polo shirt. But if you look close enough the scars of old track marks will give him away. He's used so much over the last year that he has no good veins left.

He started out on pain pills 10 yrs ago. I've lost count of his over doses. He's been on life support due to a head injury incurred while trying to break into a pharmacy. He's spent 6 months in jail, he's been jobless and homeless.

Many years ago I accepted that I was powerless to help him. A therapist helped me to learn to separate the addict from the son I love.

He admits to cutting back on his heroin use and he'll be going into inpatient rehab soon. Perhaps he'll come out with a better understanding of his addiction. Perhaps he'll stay clean for some time. He'll always be fighting that monkey on his back.

Your comment

Thanks for sharing your experience. You sound like a wonderful mother who is doing her best to help her son with his addiction. I wish you both well.


Everything you said, i am sorry to say for me is total rubbish. if there was any proof of what you say we would know already. psychology and environment socio-economic factors are all more important than so called genetics.

Your comment

Despite the fact that your comment displays both ignorance and rudeness, I am going to leave it in the feed and follow it with this reply.

If you click on the links in the article, you will be taken to studies published in quality peer-reviewed journals, as well as sites devoted to addiction at the National Institutes of Health and other reputable sites. Every statement made in this blog is based on solid scientific evidence. I didn't write this blog based on my favorite theory or my own preconceived notions about addiction. It is a careful summary of an enormous literature on this subject.

Your statement is simply false and apparently based on nothing more than myopic prejudice. I advise you to read more about the neurobiological and genetic underpinnings of addiction.

Really good article...but

Liked your article. However, I take exception to this statement:

The answer is D—they all hyper-stimulate the brain's reward system, eventually resulting in brain damage.

Is it really damage? While some addictive drugs can cause damage (alcohol), others do not - nicotine. Nor do behavioral addictions result in "damage".

I prefer the word adaptations. This recent review by Eric Nestler does a great job of summing this up: Cellular basis of memory for addiction.

To quote Nestler:

Moreover, it is striking that most addiction-related forms of plasticity are very similar to the types of plasticity that have been associated with more classic forms of “behavioral memory,” perhaps reflecting the finite repertoire of adaptive mechanisms available to neurons when faced with environmental challenges. Finally, addiction-related molecular and cellular adaptations involve most of the same brain regions that mediate more classic forms of memory, consistent with the view that abnormal memories are important drivers of addiction syndromes.

Your thoughts?

Your comment

Thanks for your thought-provoking comment. I believe we may have understood the point of Nestler's article differently.

The core of learning is neural plasticity. When the brain learns something, genes are expressed, proteins are formed, synapses are modified, and structural changes in neural circuits occur. Drugs (as well as food, for that matter) have the same effect.

The questions with respect to drug addiction are (a) the nature of this plasticity, and (b) its limits. The former is what I alluded to in the article—different drugs impact the brain in different ways. As Nestler points out

"Chronic exposure to stimulant drugs of abuse increases the dendritic spine density of medium spiny neurons of the NAc, a change that predominates for Dl-type neurons. Induction of spines has been associated for the most part with sensitized behavioral responses to these drugs, although some evidence conflicts with this view."


"Surprisingly, opiate drugs of abuse exert the opposite effect and reduce dendritic spine density of NAc medium spiny neurons. Little is known about the behavioral consequences of this adaptation and the underlying molecular mechanisms involved. This phenomenon is, however, surprising, given that CREB and ΔFosB are induced by both stimulants and opiates and are both implicated in stimulant-mediated induction of NAc dendritic spine density. This raises the question of how opiates suppress NAc spine density despite their induction of these factors."


"The other major form of morphological plasticity seen in drug abuse models is the physical reduction in cell soma size of VTA dopamine neurons induced by chronic opiate administration. A similar adaptation occurs in response to cannabinoids. This shrinkage of VTA dopamine neurons, which occurs with opiate self- administration and has been documented in human heroin addicts examined postmortem,77 seems to mediate reward tolerance and is associated with reduced dopamine release in the NAc."

Shrinking of neurons, reduction in receptors, and other phenomena are indeed types of brain damage. That is where the second question comes into play: Can these structural changes be reversed? And that is still very much an open question.

For example, according to the National Institute of Drug Abuse

"Some of the neurobiological effects of chronic methamphetamine abuse appear to be at least partially reversible. In the aforementioned study, abstinence from methamphetamine resulted in less excess microglial activation over time, and abusers who had remained methamphetamine- free for 2 years exhibited microglial activation levels similar to the study’s control subjects. Another neuroimaging study showed neuronal recovery in some brain regions following prolonged abstinence (14 but not 6 months). This recovery was associated with improved performance on motor and verbal memory tests. But function in other brain regions did not recover even after 14 months of abstinence, indicating that some methamphetamine induced changes are very long lasting. Moreover, methamphetamine use can increase one’s risk of stroke, which can cause irreversible damage to the brain. A recent study even showed higher incidence of Parkinson’s disease among past users of methamphetamine."

So I stand by my statement that long term abuse of addictive substances can and does results in morphological as well as functional changes in the brain that in common parlance can be described as brain damage.

Thanks for the exchange of ideas.

My concern is behavioral addictions

I'm going to suggest hat these changes still do not constitute "damage".

The changes you describe - Up regulation and down regulation of receptor density, increase or decrease of synaptic spine density occur naturally. Even cell atrophy can occur under certain circumstances.

I am not arguing against the biological cause of addiction. Quite the contrary. My interest is behavioral addictions, which I consider every bit as real as drug addictions. As Nestler has described in many of his reviews, these shared constellation of mechanisms and brain changes that occur with drug addictions, also occur with n behavioral addictions. So far the research points to this being the case.

My concern is that when we use the word damage to describe the brain changes caused by drug addiction, it gives ammunition to those who want to negate behavior addictions. They proclaim - "are you staying that gambling causes brain damage".

Of course, we know that is a red herring. It's not gambling, or alcohol that causes what you call "damage" - it's addiction that causes the brain changes. As nestler and others have demonstrated - all addictions share upregulation of very specific translation factors (CRED DeltaFosB), in very specific cell types, that leads to certain genes activate - results in the cellular changes described above. Simply, normal cell adaptations run amok, leading to the addiction phenotype.

So my view is that its not damage as a lay person would imagine - but it is also not normal.


your comment

I appreciate your concern that behavioral addictions--incorrectly--may not be taken as seriously as drug addictions. But the point of the article is that chronic over-stimulation of the brain's reward circuitry is what leads to addiction.

It doesn't matter whether the over-stimulation is due to chemical agents or to behaviors, such as gambling or sex. What you call adaptations are indeed changes in the brain as it attempts to put the body back into hormonal homeostasis, but these "adaptations" can yield impaired cognitive and/or affective function.

Cell death (apoptosis) is "normal" as well in that it occurs at particular rates during the lifetime of an individual. Cancer is apoptosis run amok, and can be described as an adaptation in the way you describe. But it still remains that accelerated cell death is indeed damaging to the body.

So I stand by my claims, which, incidentally, are consistent with NIH, NIDA, and CDC positions on long term deleterious effects of addiction.


reply to BS

I think it has EVERYTHING to do with genetics and nothing to do with socio-economic factors. They are an illusion.

My older sister is an addict. So are my parents and grandparents. I, somehow, through no "fault" of my own, or choice for that matter am not. I grew up in the same household. Experienced the same level of dysfunction and yet she's an addict and I'm not. I used to think that made me better. I've since come to realize that I just got genetically lucky. Just like my sister got the brown eyes and brown hair from my dad's side and I got the blonde hair and blue eyes of my mother's side -- neither of us chose those things. I'm 5' tall. Again, not a choice. I could go on, but hopefully you get the point.

It is an illusion that we choose much of anything. Coke or Pepsi? Well, one has more sugar in it and if your body likes the sugar content, you probably like Pepsi better. And, you probably think that was a choice.

your comment

Thanks for sharing your real-life experience. It is indeed informative.

Thank you

Doctor, thank you for you comprehensive and accessible explanation of the physiology of addiction. As a person not in the healthcare field, I found this article enlightening and informative. You should publish this article in print in popular magazines and newspapers to inform the public how addiction happens.

Your comment

Glad you enjoyed the article, Carol. I am glad you found it informative. Feel free to share it with others that might benefit from this information.

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Denise Dellarosa Cummins, Ph.D., is the author Good Thinking, The Historical Foundations of Cognitive Science, and Evolution of Mind.


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