Jezebel took a few extra jabs reporting it, is all. Sounds like the book and the Bloomberg article are stone sober:
Now at the University of Cambridge, Coates turned to neuroscience after working for a decade at Goldman Sachs Group Inc. and Deutsche Bank AG, where he ran a trading desk. Even before his experiments, his practical experience during the dot- com bubble convinced him that the markets were running on something deeper than dispassionate reason. Normally “a sober and prudent lot,” as he recalls, “traders were becoming by small steps euphoric and delusional.” They were “overconfident in their risk-taking, placing bets of ever-increasing size and ever worsening risk-reward trade-offs.” As much as traders and investors try to remain rational, will power is no match for steroids that work their effects in every single cell in the body.
http://www.bloomberg.com/news/2012-06-10/what-traders-testosterone-tells-us-about-markets.html