Julian M. Whitaker is an MD, a practitioner of alternative medicine, and a promoter of vitamin cures and other alternative therapies through the Internet, self-published newsletters, and books. He is also a certified ardent fan of the Galileo gambit. His day job is to run the Whitaker Wellness Institute in California and he has previously been president of The Alliance for Natural Health USA (who knows).
Whitaker is apparently board certified in “anti-aging medicine” by the American Board of Anti-Aging & Regenerative Medicine, an educational and certification program of the American Academy of Anti-Aging Medicine, which rather unsurprisingly shows up here.
Whitaker opposes the use of pharmaceuticals in the treatment of mental illness and believes that psychiatry is fraudulent. In a CNN interview with Anderson Cooper, he claimed that psychiatric diagnoses have “no basis” and are fabricated or voted into existence by powerful groups of doctors with financial interests. Whitaker, who promotes himself as “America's #1 health advocate,” “America's #1 health champion,” and “the physician America trusts”, and whose vitamin recommendations seriously lack evidential support, apparently doesn’t see the irony here (he also serves as a consultant to vitamin companies advertised on his website). As an exercise, you could try to count the fallacies in his foreword to Suzanne Somers’s quackery-promoting book on cancer (or see here if you can’t be bothered to).
As opposed to many quacks, Whitaker does not seem to have mastered the Gish gallop, and since science and reason cannot quite back up his positions, his anti-vaccine arguments got rather badly slaughtered in a debate with Steve Novella at FreedomFest.
Diagnosis: It’s hard to determine what’s mere crackpottery or willful ignorance and what's something more insidious in cases like these, but Whitaker is a rather dodgy person – one of far, far too many.