addiction, genetics and early brain development

image of a fetus.  what is its brain development?in a comment yesterday on my article on some research on adult children of alcoholics, CP stressed the importance of genetics in alcoholism.

i would like to contrast that with another point of view. gabor mate offers this theory in his book in the realm of hungry ghosts: close encounters with addiction

brain development in the uterus and during childhood is the single most important biological factor in determining whether or not a person will be predisposed to substance dependence and to addictive behaviours of any sort, whether drug-related or not.

this is shown, among others, by dr. vincent felitti, chief investigator in a landmark study of over 17,000 middle-class americans.

mate goes on to say that

to state that childhood brain development has the greatest impact on addiction is not to rule out genetic factors. however, the emphasis placed on genetic influences in addiction medicine … is an impediment to our understanding.

he makes the case that there are four important brain systems in addiction, and that they are all exquisitely fine-tuned and changed by the environment – and particularly by the environment that a human being experiences in the womb and in the first few years of life:

  • the opioid attachment-reward system (involving endorphins)
  • the dopamine-based incentive-motivation apparatus
  • the self-regulation areas of the prefrontal cortex
  • the stress-response mechanism (involving a decrease of opioid and dopamine receptors)

in other words, during pregnancy and the first years of life – and to some degree, on to teenage years – the brain grows and develops, sometimes at a dizzying rate (at times 250,000 neurons are added every minute!) the vast majority of brain development occurs during pregnancy, however. so what is often attributed to genetics can already have happened during pregnancy.

attachment – how we bond with others – is intimately linked to our reward system. going for addictive substances or activities is a misplaced attempt to reward oneself.

motivation is what gets us going. most of the time, we need an incentive to motivate us. if the right connections weren’t made in the brain when we were small, we might find addictive behaviours or substances more motivating than anything else.

our mood, levels of motivation, energy levels, and ability to withstand adversity need to be in a certain, well-tuned balance in order for us to function well. this is related to homeostasis, a type of inner thermostat or self-regulator that keeps all of these elements on a relatively even keel. again, this homeostasis depends on the brain having “learned” about it. if it’s out of kilter, we can do things like self-medicating with drugs – a (usually unconscious) attempt at reaching homeostasis. this is also closely related to our stress response mechanism.

(image by hive)


  1. Great Blog I agree with the comment “childhood brain development has the greatest impact on addiction is not to rule out genetic factors. however, the emphasis placed on genetic influences in addiction medicine … is an impediment to our understanding. ”

    Thanks for sharing
    Jim Signs

  2. Very interesting read. Addiction is a very serious matter. There is alot o research to be made still. But i am hopefull that some day these problems will be dealt with easier.

    Lauren’s last blog post..Find Great Blogs

  3. hi C-P – i think the crucial sentence here is that the brain is “exquisitely fine-tuned and changed by the environment.”

    elsewhere in the book, mate explains the role of environment and genetics with the example of a seed. for sure, the seed brings a certain structure but whether it lives or dies and how it thrives all depend on the environment (soil, water, light, temperature, etc.).

    the brain’s environment in the womb is the mother’s nutrition and her complex hormonal responses to HER experience and environment.

    for example, if a pregnant woman is beaten by an alcoholic partner, her body’s chemical responses (e.g. highly increased adrenalin) will influence the unborn child.

  4. i think i’d see it similarly.

    except i would be hesitant to use the word “determines”. it looks to me that nothing in the human experience is ever determined – but there are certain tendencies that increase or decrease the likelihood of something happening.

  5. isabella – Thanks for these stimulating posts on addiction and adult children. I agree with the concept of the family environment having a big impact on whether inherited tendencies will actually emerge as disorders. The study on adult children sounds excellent in getting at the complexity of the relationship of individual and family. Mate’s view captures the intense and unbalanced reactions to brain chemistry of people who become addicts. Thanks for introducing me to these interesting studies – I need to go read them!

  6. Addiction is definitely a problem with the brain but they are also looking into the rest of the body’s reaction to whatever it is they are addicted to for answers as well.

    Dante’s last blog post..Learned

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