His bio states: "Gregg Henriques, Ph.D., author of A New Unified Theory of Psychology, directs the Combined Clinical and School Psychology Doctoral Program at J

His bio states: "Gregg Henriques, Ph.D., author of A New Unified Theory of Psychology, directs the Combined Clinical and School Psychology Doctoral Program at James Madison University. He is a licensed clinical psychologist..." You're right that he isn't a psychiatrist, but he is a clinical psychologist. My educated layman's understanding is that this informs the more behaviorally/environmentally-driven view in his article, but because psychiatrists are trained from a traditional medicine/biology-focus, they are just as likely to be shifted towards the (also valid) biochemical explanations of depression (and the pharmaceutical treatments).