Addicted to neurobiology and politics

ABC Radio National’s All in the Mind has just had a special edition on the increasingly contentious debate over whether addiction is a brain disease, and does a fine job of highlighting the politics behind the interpretation of the science.

This much is agreed upon: some people inherit a greater propensity for becoming addicted to certain drugs, and taken in enough quantities, some drugs can cause long-term alterations the brain’s reward system to make non-drug pleasures less rewarding, thereby increasing future chances of drug-taking.

The controversial issue, which All the Mind tackles, is over how much this should be described as a ‘brain disease’ or a ‘psychological problem’, and this is usually where the politics kicks in.

Whenever you hear this sort of rhetoric in mental health, it’s often a reflection of a deeper argument beneath the surface – an argument over how much someone is personally responsible, or more worryingly, ‘to blame’, for their state of distress or impairment. The same often goes for the ‘genes vs environment’, ‘nature vs nurture’ debate.

There is a condition which is a great example of how thinking only in terms of ‘mind or brain’, ‘genes or environment’ is flawed for anything which involves an external trigger.

Phenylketonuria (PKU) is a single-gene disorder that results in a missing enzyme which is needed to break down phenylalanine into the building blocks of certain neurotransmitters. Without the enzyme, phenylalanine accumulates in the body, leading to problems with brain development, cognitive impairments, seizures and psychosis.

However, if people with PKU avoid phenylalanine in their diet, they have no problems at all (this is why certain foods are marked with “contains a source of phenylalanine”).

So, is PKU a genetic disorder or an environmental one? A brain disease or a psychological problem? There is no single answer. It depends how you look at it.

In a sense it’s 100% genetic, because a single gene determines whether you have the missing enzyme or not. But in another sense, it’s 100% environmental, because it’s not a problem unless you encounter phenylalanine in the environment.

Similarly, you could say it’s a brain disease, because people with PKU inherit a problem with the neurotransmitter pathway, but in another sense, it’s a psychological problem, because poor diet decision-making and vigilance can determine the likelihood of becoming sick.

What is striking is that this division into ‘brain’ and ‘mind’ is completely artificial and counter-productive. You need to understand both to see how PKU affects someone’s life.

Buy you’ll also notice how political views could favour one view or another.

If you believe in the primacy of personal responsibility, push the psychological model, because this emphasises the affected person’s actions in staying well. At one extreme, it allows us to blame people who get sick through PKU for not being vigilant enough, or wanting other people to pick up the pieces when they fail to control their diets.

If you believe in the primacy of social responsibility, push the disease model, because this emphasises the effects of factors outside an individual’s control. At the other extreme, it allows us to absolve the person of individual responsibility for the effects of their illness.

Addiction is far more complex than PKU, not least because addiction to different substances, or indeed to behaviours such as gambling, can be quite different psychologically, neurologically and socially.

However, you can see how the models used to explain each disorder are selective or can go beyond the evidence in certain instances, so preference for an explanation can be politically biased.

My advice is to be suspicious of anyone who tries to tell you a complex disorder is purely mind or purely brain, and think about what is motivating someone to explain it largely in one way.

Similarly, think of the psychological and neurobiological evidence as complementary, rather than in competition, and be prepared to accept more than one model of how something works. Each might be accurate, but just useful for different things.

This edition of AITM is an example of all of these forces at work.

Link to AITM ‘Addiction: Dis-ease over diseased brains’.

3 Comments

  1. Posted August 19, 2007 at 11:07 am | Permalink

    I think this puzzling aspect face by neuroscience has tremanedous impact in society and policy and also deals with the old and perennial debate in the western philosophical reflection and tradition: such us the metaphysical issue of free will.
    I¬¥m lean to think that in some sense we are genetically prone to suffer addictions, so for me is more a matter of “brain disease” wth a mixture of “psychological problem” due to the multifactorial bidirectional relations of having certain anomalies in our genetic make-up.
    Moreover, if neuroscience can tell us something about this kind of behaviour (addiction)we can override any impulse to stigmatize and exclude people with addictions if we know that they are less culpable of their behaviour (this also is important in free will debate about compatibilists, incompatibilists, determinists,libertarians, semi-compatibilists…) that is, because neurosicence could demonstrate that they are not responsible for their conduct because they lack internal control of theirs “motivations”.

  2. Mark(p.s.)
    Posted August 20, 2007 at 11:09 pm | Permalink

    Great post!

  3. Sally
    Posted September 24, 2007 at 5:59 pm | Permalink

    I think it’s odd that the addiction question is couched in terms of brain disease versus psychological problem and that those in the addiction field still think having a condition labeled a brain disease will reduce stigma. In the field of psychiatry, the prevailing idea is now that there are no psychological problems, but instead that every bit of mental discomfort and distress is a brain disease. This has resulted in a huge increase in stigma. Once you are labeled as having a disease that makes you unable to be responsible for your actions, you lose the right to due process in our nation. Furhtermore, in our hysterical society, addiction is overdiagnosed almost as much as child bipolar disorder. The only successful way to treat addiction is the support group model, 12 step or otherwise, because addiction is a social problem not a brain disorder or even a psychological problem.


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