Your question Are 10% of mental health problems caused by abortion might be addressed in a number of ways. First, in considering whether there is any evidence to support the claim, one could simply go to the source studies that were included in the meta-analysis. (You may find the referenced studies for free at http://bjp.rcpsych.org/content/suppl/2011/08/11/199.3.180.DC1/bjp_199_ds180.pdf . The full PDF costs $15.)
Many of the source studies (Cougle 2008 (US), Pergrusson 2008 (Australia), Gilchrist 1995 (UK) and others) report the increase in mental health problems. All of the articles were published in refereed journals, which means that skepticism is built in, as many experts in that field will try to pick apart a submission. By the way, the nature of a meta-study is not to make new claims, but to summarize existing claims.
Canadian authors Mota, Burnett, and Sareen published a study entitled “Associations Between Abortion, Mental Disorders, and Suicidal Behaviour in a Nationally Representative Sample” in the Canadian Journal of Psychiatry, Vol 55, No 4, Aprtil 2010. This article was not cited in the Coleman’s meta-analysis, and yet confirms the same results.
When compared to women without a history of abortion, those who had an abortion had a 61% increased risk for Mood Disorders. Social Phobia was linked with a 61% increased risk and suicide ideation with a 59% increased risk.
So yes, there is evidence to support the claim.
Let us examine the detractors of the article.
One of the strongest, most cogent critiques of Coleman’s meta-analysis may be found at http://bjp.rcpsych.org/content/199/3/180/reply#bjrcpsych_el_33923 .
Here is an outline of objections from Louise M Howard, Hind Khalifeh, Melissa Rowe, Kylee Trevillion, and Trine Munk-Olsen.
- Did not follow robust methodologies for systematic reviews
1a. No details on search terms
1b. Only two databases included
1c. Lacks citation tracking
1d. Non-standardized measure of mental disorders
1e. Lack of adjustment for pre-existing mental illness
1f. No adjustment for key confounders.
- Munk-Olsen, the last author of the critique, published in the NEJM that “reported no difference between the incidence of first psychiatric contact before and after abortion.” (7. Munk-Olsen, T., et al., Induced first-trimester abortion and risk of mental disorder. N Engl J Med, 2011. 364(4): p. 332-9)
- Eleven of the twenty-two papers were authored by Coleman.
- Synthesis of the data and summary statistics are flawed.
- Erroneous conclusions drawn regarding the Population Attributable Risk (PAR).
I would respond to the Howard, et. al. critique:
- The lack of citations doesn’t invalidate the meta-study. Lack of key confounders means the critique suggests that Coleman did not account for problems such as social deprivation or rape. On the other hand, it also means that Coleman did not “cherry pick” patients just to prove her point.
- Munk-Olsen has a single study that contradicts a much larger meta-study. Unfortunately, their study did cherry pick the more healthy ones, for example, excluding women with previous psychiatric history. (See http://www.aaplog.org/get-involved/letters-to-members/danish-nejm-study/).
- While Coleman had written half of the papers in the meta-study, there are many other studies in many different countries that corroborate the meta-study. (Data table for original meta-analysis article, http://bjp.rcpsych.org/content/suppl/2011/08/11/199.3.180.DC1/bjp_199_ds180.pdf)
- The fact that there multiple effects reported in 13 of the 22 studies does not diminish the importance that there are 9 with single factors. (same site, http://bjp.rcpsych.org/content/suppl/2011/08/11/199.3.180.DC1/bjp_199_ds180.pdf)
- I think the critique is implying that Coleman uses circular reasoning: assuming that the risk factor (abortion) causes the disease (mental health problems) while trying to prove the same. I am not familiar with this particular branch of statistics and cannot confirm or dismiss the critique on this point.
To the second part of your question, Does this meta review actually support this claim adequately?, I would say “yes,” mostly because the critique does not make a compelling case. While the Howard, et. al. critique implies that Coleman is in self-interest, there may be an element of self-interest in Munk-Olsen detracting from Coleman while promoting the NEJM article (which is in the minority).
Taking a parallel line of reasoning, it is interesting to note that abortion is correlated with not only mental but physical outcomes, such as breast cancer. (See “Induced abortion as an independent risk factor for breast cancer: a comprehensive review and meta-analysis” at http://jech.bmj.com/content/50/5/481.short, for example.) The window for reproductive problems arising from abortion is limited to the time when the woman can reproduce, say twenty years. In contrast, mental problems can have a much longer delay in onset from the provocative event. For example, PTSD may occur more than twenty years after the provocative event. So the 10% estimate may be underestimating the effect. And if there are physical repercussions to abortion, it is not unreasonable to assume that there may be some mental repercussions as well.
On a different line of reasoning: there was a point when there were scientific studies that contradicted the notion that using tobacco products were correlated with lung cancer. (Of course, the tobacco companies vigorously held on to this notion.) With enough studies (and meta-studies), it became better understood that there was a strong correlation.
So in conclusion, yes and yes to your questions. The science supports the meta-study’s conclusions.