But "facts" are tricky things. A "fact" can be something that is happening out in the real world, or at least a proxy measure of something that is happening in the real world. But a "fact" can also be a problem with the way look at the world. Maslow once wisely said that "if all you have is a hammer, everything looks like a nail".
So when a group of Pennsylvania fMRI technicians report that higher rates of depression in women are explained by oestrogen causing greater blood flow to the emotional centres of the brain, I am naturally suspicious. A functional MRI scanner is a very complex and expensive hammer, and the technicians that use it are like Maslow's young boy who - given a hammer - finds that everything needs to be thumped!
Of course they want to show that their hammer is useful; not least to justify their continuing research funding. But do their findings stack up? There are several reasons for believing that they do not.
The least scientific of my objections is that the study was reported in the Daily Mail (famous for inventing "facts" about health). This does not prove anything, but it should sound a note of caution. It is sensible never to believe anything that the media in general, and the Daily Mail in particular reports about health.
A more important concern is with the study itself. The study was not a test of differences between men and women affected and not effected by depression. Indeed, the study itself had nothing to do with depression. Rather, it was an examination of brain development in 922 healthy young women aged between 15 and 22. It did not distinguish men (who were not even studied) from women, or healthy women from those with mental illnesses.
The study found that changes in oestrogen levels correlates with increased blood flow to the emotional centres of the brain as women go through puberty. But, since the study made no comparison between women with and without mental illnesses like anxiety and depression, there is no way of knowing whether this finding relates to depression at all. Indeed, since the increase in blood flow occurs in all women (not just the 1 in 10 who are diagnosed with anxiety or depression) there is good reason for believing that this finding has nothing to do with depression whatsoever.
The biggest objection concerns the way we define and measure mental illness. Psychiatrist and Radiologist Daniel Amen points out that "psychiatry is the only clinical specialism that does not examine the organ it claims to be treating". Conditions like anxiety and depression are not real, objective illnesses that can be measured in the way that we measure an infection, a broken bone or a damaged organ.Where other specialisms use blood tests, x-rays, ultrasound scans and MRI scans to see what is going on, psychiatrists make subjective (educated) guesses based on patients' descriptions of their symptoms.
The patient may be wrong or incomplete in his or her description of the symptoms. The psychiatrist may misunderstand what the patient is saying when interpreting the symptoms. This alone gives serious cause for concern about the way mental illnesses are diagnosed. But even more worrying is the way particular clusters of symptoms come to be defined as "real" illnesses that increasing numbers of psychiatrists and drug companies claim (without evidence) to be disorders of the brain. As Professor Sami Timimi points out, "most psychiatric diagnoses have been literally voted into existence". Diagnostic manuals are drawn up by groups of psychiatrists - the majority of whom receive significant funding from the pharmaceutical corporations - who vote upon which symptoms are included (and excluded) from a diagnosis.
So what if the "fact" that depression is much higher in women than men is the product of another of Maslow's hammers - that once a pharmaceutical company has a treatment, then every treatable symptom looks like an illness? Depression in men would be a lot higher if symptoms such as increased anger and irritability, and increased alcohol and drug use were included in the symptoms clusters used in diagnostic manuals. However, these symptoms are not improved by antidepressants, so they have been excluded. As such, it may only appear that more women than men have depression.
Throughout the ages, sexism has been based on unsubstantiated claims that because women are biologically different they are inevitably socially, politically and economically different too. Without care, the use of fMRI scans today to suggest that, for example, women are more prone to mental illness than men, may be little different to Victorian phrenologists feeling the bumps on people's heads to determine who would be a criminal.
There may be real differences between the sexes in predisposition to mental illnesses. But the difference could just as likely lay in the very poor manner in which mental illness is defined and measured. Either way, bad science and bad science reporting add nothing to our knowledge but a great deal to our prejudices.
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