Daniel Amen, much like any cult leader, is dangerous because he is convincing. This book is very well-written, persuasive, and does an excellent job in advancing the illusion that the advocated ADHD classification system and associated treatments are supported by research.
The most frightening aspect of this is the fact that people who suffer from ADHD, a very real and very serious condition, are buying into Amen's snake oil and banking their hopes on its effectiveness. Like any treatment that is successfully marketed, it undoubtedly carries a substantial placebo effect that, in the absence of replication by other researchers using similar techniques, makes it impossible be validated. While SPECT may be a useful imaging technique, NOBODY has made use of it in a manner even remotely close to that which Amen indicates. His classification (the "6 types") and treatment recommendations are utterly unsupported by science and contrary to volumes of sound research from a diversity of sources. As such, Amen's HYPOTHESES, when put into practice, carry great risk.
It remains to be seen whether Amen is a genius or zealous snake oil salesman driven by greed. Despite my great reservations about his position and my belief that he is the latter, his HYPOTHESES may ultimately be found to be valid. However, until such a time comes that others (who do not benefit financially from positive results) replicate his findings, his diagnostic and treatment practices should be considered EXPERIMENTAL, UNPROVEN, and POTENTIALLY HARMFUL. Moreover, Amen exhibits the highest degree of ethical disregard by promoting his position as valid and empirically supported.
Readers should be advised that Amen is far out of the mainstream and his practice may be akin to past life regression, abuse memory recovery, rebirthing, and other treatments that, while appearing promising early on, were found to be absolutely invalid when viewed under the bright light of scientific inquiry.