Hi there

You may find some info at PsychCentral. If you use the Search function, it'll bring up some topics on the SCT. You could try searching "Slow Cognitive Tempo", "Underarousal", "Slow Cognitive Processing Speed" as well as "Sluggish Cognitive Tempo".
http://psychcentral.com/

http://psychcentral.com/blog/archive...nst-the-dsm-5/
Some of the Empty Arguments Against the DSM-5
By John M. Grohol, Psy.D.

eg. http://blogs.psychcentral.com/adhd-z...ould-you-care/
DSM Revisions and ADHD: Should You Care?
By Zoë Kessler, BA, B.Ed.

That's just a couple. There are many more.

http://www.tourettesyndrome.net/diso...-in-adulthood/
ADDults: ADHD in Adulthood
by Leslie E. Packer, PhD

Russell Barkley, PhD might be someone to search for - He's mentioned in the research background of DSM section on ADHD and elsewhere.
http://www.dsm5.org/research/pages/e...der,juven.aspx

http://www.adhdbasics.org/ref/DSM-V.pdf
from DSM-5 development page
Draft DSM-V Criteria for ADHD
(changes italicized)

Not totally sure if that last link is totally up to date.

Gosh, all this DSM-5 info seems all a bit top-secret to me after trying to find more. I guess if it's added in the new Edition we'll only find out when the book is released. lol sheesh.