What do antidepressants do?

grey_shadow_pills.jpgThere’s a thought-provoking piece in the latest issue of open-access medical journal PLoS Medicine on whether antidepressants ‘correct’ a problem in the brain, or just create an altered state that may be useful for people with low-mood problems.

It is notable that the way psychiatric drugs are described is usually because of marketing. For example, SSRIs are classed as ‘antidepressants’, dopamine agonists and ‘antipsychotics’ and drugs like sodium valproate as ‘mood stabilizers’.

These terms have been promoted by drug companies in an effort to establish a market for particular compounds and imply that they directly affected these conditions. Often, they have been invented to replace previous labels which were no longer useful in marketing the drug.

The authors of the PLoS Medicine paper argue that trials have shown that, for example, opiates and amphetamine-like drugs can have beneficial effects in depressed patients but are not considered ‘antidepressants’.

The paper also tackles the idea that depression is ’caused by low serotonin’ in the brain and that antidepressants ‘correct’ this problem.

The low serotonin theory of depression must rank as one of the most widely known and least supported scientific theories, as there is comparatively little evidence that backs this explanation.

The authors argue that instead of trying to explain the action of a drug in terms of a disease it is meant to ‘correct’, it is more accurate to describe the drug in terms of its general actions in the brain which could be coincidentally useful in treating certain conditions.

I suspect, this is what inevitably happens anyway, owing to the needs of marketing.

Typically, when a drug is discovered, it is targeted at a condition which is likely to be profitable (depression being the classic example). At this point, it is usually marketed as an anti-something-or-other.

Later, when the profits begin to come in, the pharmaceutical company looks to widen the market and tests it on other, less prevalent, but hopefully still profitable conditions (e.g. social phobia).

For example, SSRI drugs (such as Prozac) are now indicated for depression, PTSD, obsessive-compulsive disorder, eating disorders and panic disorder to name but a few.

The marketing then begins to place less emphasis on its original label, so it is seen as more wide acting.

Have a look at the archives of the front page of the Seroquel website before and after it gained approval for the treatment of bipolar disorder and notice how the term ‘antipsychotic’ is suddenly not so prominent.

Perhaps to put the paper in context, psychiatrist Dr Joanna Moncrieff, one of the authors of the PLoS Medicine paper, is co-chair of the Critical Psychiatry Network – a group of psychiatrists who dispute the predominance of biological models of mental disorder and campaign for a less coercive psychiatry.

Link to PLoS Medicine article ‘Do Antidepressants Cure or Create Abnormal Brain States?’

One Comment

  1. Posted November 12, 2006 at 11:17 pm | Permalink

    Well, you’re right about the labels, but it’s not the drug companies’ fault.
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    The labels “mood stabilizer,” and “antidepressant”, etc, aren’t labels promoted by drug companies; they are the postulates, the signs of psychiatry. Psychiatry desperately needs these signs because they provide a (arbitrary and artificial) structure upon which psychiatry can supposedly grow. It gives it the illusion of being a science.
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    I’ll give you an example: can an antipsychotic be an antidepressant? Sure. Can an antidepressant be an antipsychotic? See how that seems less possible? The reason you are hesitating is because you are mired in this semiotic trap. In reality, the terms antidepressant and antipsychotic say nothing other than “drugs that treat X”– there’s absolutely no way the terms can a priori determine other efficacies, side effects, pharmacologic actions, etc,– but psychiatry uses them to carry precisely this kind of information.
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    Here’s a more specific example. Seroquel recently received FDA approval for the treatment of bipolar depression. Does that make it an antidepressant? Since it does, does that mean it now caries all the risks of other antidepressants, notably the suicide risk? Well, the FDA thinks so, because it placed a warning about it. But understand that prior to that FDA warning, Seroquel “was not” an antidepressant and thus did not have those risks; now, with the label change, it “is” an antidepressant and “does” have those risks.
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    That’s not science. The problem with the biological model of psychiatry is that even if there was one, the current language of psychiatry would prevent any meaningful investigation of it.
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    If you are interested, here are two posts which talk about this in more detail:
    More about the Seroquel disussion:

    http://thelastpsychiatrist.com/2006/11/the_charade_is_revealed_we_are.html

    Semiotics and psychiatry:

    http://thelastpsychiatrist.com/2006/11/massacre_of_the_unicorns.html


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