In the case of , only a handful of barely adequate studies on a small number of people have been conducted in the past few years. We will explore these more fully in the chapters that follow. First, it is important to lay out three important limitations that are already beginning to emerge from this research. All are quite consistent with what we already know about the biological and genetic bases of other conditions. First, like all complex behavioral and mental states, is multifactorial. It is neither exclusively biological nor exclusively ....