The GLP is committed to full transparency. Download and review our Annual Report.

Is childhood trauma linked to depression? Why this paper may have overestimated the impact

| | May 21, 2019

A paper in PNAS got some attention on Twitter recently. It’s called Childhood trauma history is linked to abnormal brain connectivity in major depression.

Now, I think that this talk of dramatic scarring is overblown, but in this case there’s also a wider issue with the use of a statistical method which easily lends itself to misleading interpretations – canonical correlation analysis (CCA).

CCA is a method for extracting statistical associations between two sets of variables. Here one set was the 55 brain connectivity measures, and the other was the 4 clinical clusters. Yu et al.’s CCA revealed a single, strong association (or ‘mode of variation’) between the two variable sets:

Related article:  Fasting as a treatment for Alzheimer’s? Preliminary research indicates benefits

A correlation coefficient of 0.68 is very large for a study of a brain-behaviour relationship. Normally, this kind of result would certainly justify the term “dramatic association”.

But the result isn’t as impressive as it seems, because it’s a CCA result. CCA is guaranteed to find the best possible correlation between two sets of variables, essentially by combining the variables (via a weighted sum) in whatever way maximizes the correlation coefficient. In other words, it is guaranteed to over-fit and over-estimate the association.

Read full, original post: Scarred Brains or Shiny Statistics: The Perils of CCA

The GLP aggregated and excerpted this article to reflect the diversity of news, opinion, and analysis. Click the link above to read the full, original article.
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.

Send this to a friend