A biopsychologist deeply skeptical of the widely accepted biochemical approach to mental illness presents a well-documented argument against it. Valenstein, a professor of psychology and neuroscience at the University of Michigan, is convinced that neuropharmacology has not brought us closer to understanding the origin of mental disorders or even to how drugs may help alleviate these conditions. After sketching the history of psychotherapeutic drugs and the revolution in thinking about mental illness that followed their discovery, he examines the research behind theories developed to explain how these drugs work. Looking closely at depression and schizophrenia, he finds the evidence supporting claims that these mental disorders are caused by specific biochemical imbalances to be decidedly weak and the claims that drugs are the answer to be greatly overstataed. Valenstein really bristles at the analogy commonly drawn between treating diabetes with insulin and treating mental disorders with psychotheapeutic drugs, a comparison he finds especially flawed. He takes the pharmaceutical industry to task for what he considers its exaggerated promotional claims directed at both physicians and the public, but he also cites psychiatrists for their too-ready acceptance of drug therapy (a treatment mode that competing nonmedical therapists cannot offer), researchers and clinicians for allowing themselves to be subtly influenced by the drug industry, HMOs and insurers for reimbursement policies that favor relatively quick and inexpensive drug therapy over time-intensive talk therapy, and patients for preferring to believe their problem is a mere chemical imbalance rather than a potentially stigmatizing mental illness. When uncritical acceptance of the biochemical theory of mental illness is widespread, other important factors--psychological, interpersonal, and even environmental--tend to be overlooked, cautions Valenstein. He is keenly aware that his message will meet stiff resistance from various quarters, and in his final chapter, he attempts to answer anticipated criticisms. May not make many converts, but should stimulate a brisk discussion among psychiatrists and other interested parties.