We knew it was bad for you, see!?!

A sample of the headlines:

Don’t you just love the way the MSM so baldly states its beat-up of the day? Of course the study isn’t the slam-dunk they present it as. Here are the key findings of the study, led by psychologist and epidemiologist David Fergusson at the Christchurch School of Medicine and Health Sciences, published this week in the Journal of Child Psychiatry and Psychology:

  • Researchers found 41 per cent of the more than 500 women in the study had become pregnant by age 25 with 90 pregnancies terminated.
  • At age 25, 42 per cent of those who had an abortion had experienced major depression at some stage during the previous four years – nearly double the rate of those who had never been pregnant.
  • The risk of anxiety disorders was also raised by a similar degree.
  • Women who also had at least one abortion were twice as likely to drink alcohol at dangerous levels and three times as likely to be dependent on illicit drugs.

The team seems to have been epidemiologically sound enough in their comparisons, and as a pro-choice atheist Fergusson is clearly disturbed by the political implications of the trends his team discovered. The team compared the abortion group to women of their cohort who had never been pregnant, and those who had continued their pregnancies. The trends do appear to hold, although I see no indication that there was any comparison with women who had continued with unplanned pregnancies, a distinction I would think crucial.

But do these trends necessarily show that it is the decision to have an abortion that causes mental illness and/or substance abuse in later life? After all, although the sample size of the study as a whole is reasonable (1265 New Zealanders, male and female, tracked from birth) the sample size of women who’ve had an abortion is only 90.

Now, already some sensible folks have written about the limitations of the study, mostly dealing with the screamingly obvious fallacy of correlation implying causation (which can be used to demonstrate that giving women the vote led to two world wars, just as you always suspected). A woman who knows she has a personal and/or familial history of mental depression may make an informed choice not to be a mentally ill parent, so she may have an abortion and later suffer an depressive episode. That does not mean that the abortion led to her depression.

To move away from data to anecdote:

As an example of depressive illness influencing parenting decisions, I had severe PND with both my kids. Having also coped with a long ongoing case of chronic depression in my early 20s, I decided that I wouldn’t be having any more children, as having a mum with continuing episodes of depression I felt would be less than ideal for the two kids I had already, let alone any future sprogs. We went the route of a vasectomy for my husband, so abortion never entered the picture for me.

But if I had required an abortion (if, say, my husband’s vasectomy hadn’t worked), I don’t see how a simple study like Fergusson et al could differentiate between someone prone to depression making a responsible decision about parenting capacity and later having a not unprecedented depressive episode, and someone with no known history of depressive tendencies having an abortion and later having a depressive episode.

Another key point about familial depression, until my own first episode, I didn’t know my family had a history of depressive illnesses because nobody ever talked to us kids about it. Then I got to hear about Cousin X, and Great-Aunt Y, and Uncle Z and all their doolally forebears in the family tree.

So a young woman ignorant of her predisposition to familial mental illness may well be more vulnerable to exactly the impulsive behaviours that make unplanned pregnancies more likely, as well as being predisposed to depressive episodes later in life. Same-same for abuse of alcohol and illicit drugs.

Back to the data: The causative link explaining the trend found by Fergusson et al may well be more to do with the not unreasonable supposition that women prone to varying degrees of mental instability are more likely to have an unplanned pregancy, and therefore are more likely to have an abortion than their more neurotypical peers. This is however merely an hypothesis to be tested: the answer could be something else entirely. We simply don’t have enough data examined thoroughly enough yet to know.

Fergusson et al is a valuable study that doesn’t deserve to have its other findings buried in the avalanche of noise the abortion controversy is going to pile upon it. But it is not complete, and the epidemiologists don’t claim that it is. They have found an intriguing trend that cries out for further investigation. Let’s hope that they get the funding to continue their studies and further inform the debate on reproductive choice.

UPDATE: more on this at Pandagon and Capitalism Bad: Tree Pretty

Categories: culture wars, media, medicine

Tags: , , ,

6 replies

  1. So mad with the stupid spin on it all, although it is partly the fault of the researchers, reading the quotes they gave the local papers.I discovered a friend of mine is part of the longitudinal study they got this information from. To me the longitudinal study is the important bit, this can’t answer any questions, because it’s not designed to do so (particularly if they didn’t compare those who kept an unplanned pregnancy with those who terminated it – possibly because they didn’t even ask if pregnancies were planned)

  2. Yup: mining this trend from a longitudinal study places severe limitations on the value of the results. It’s a trend that cries out for further investigation, that’s all.And don’t be too hard on the researchers. Poor bunnies – they get up in front of journalists to make a nice rational statement of their findings, then they hve to grit their teeth and answer stupid questions politely, only to find that the soundbites chosen are not the carefully worded official statement but the off-the-cuff answers, which are often not much more sensible than the questions they’re answering.

  3. There’s a full page article in today’s Herald from the researcher where he seems to suggest that this backs a pro-life position on abortion. They also talked up the findings yesterday as being hugely significant, as if this sort of research hasn’t been done before.I don’t have a lot of sympathy for him.

  4. Was that this <a http://WWW.NZHERALD.CO.NZ/SECTION/STORY.CFM?C_ID=5&OBJECTID=10362476 = HREF rel=”nofollow”>article? He does sound awfully defensive about the criticisms of the study.Professor Fergusson said the results could not be argued away by assuming the women involved already had mental health problems or “a pre-disposition”. ”We know what people were like before they became pregnant. We take into account their social background, education, ethnicity, previous mental health, exposure to sexual abuse, and a whole mass of factors.”So why haven’t the correlations, whether weak or strong, with these other factors been better publicised? And even if someone answered “no” to a question on familial mental illness, how do they know about their own family? Nobody ever told me there was mental illness peppering the family tree until my first episode.That said, I don’t think his statement ”I’m pro-choice but I’ve produced results which, if anything, favour a pro-life viewpoint” is a strong statement that he really believes the study supports the anti-abortionists, just that it can be perceived that way.But he sure is enjoying his moment in the limelight, isn’t he?

  5. Viv, I think you’ve made a very good point about Fergusson enjoying the limelight. Look at the timing of the release of this report – media hungry for news, critical journalists on holiday. He has a history of producing provocative research findings, of publishing his work in obscure overseas journals, and of restricting access to his data.In contrast, Steven Levitt (Freakonomics) published some provocative findings on the link between abortion and crime, but allowed other researchers access to his data. They found an error in his workings and came out with a more moderate finding. Surely this is what good science is about. It’s a shame that someone can have access to huge amounts of public funds and yet not allow his work to be scrutinised by other researchers, using the same data.

  6. ”He has a history of producing provocative research findings, of publishing his work in obscure overseas journals, and of restricting access to his data.”Ooh, I didn’t know that about him. Is he the gatekeeper for all the data from the longitudinal study then?

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