In this book, the author discusses a range of common neurodevelopmental disorders affecting young people - autism, depression, schizophrenia, ADHD, Tourette's Syndrome and obsessive-compulsive disorder - from the unique perspective of their proposed common origin in the function and dysfunction of the brain's frontostriatal system. It is argued that these disorders have much in common with each other in their phenomenology, co-morbidity, genetics and neuropathology. Throughout the book, the author systematically compares and contrasts them from a biological, clinical and evolutionary standpoint, viewing them as extensions of normal personality attributes, which, in less extreme form, may possess certain behavioural advantages, explaining their persistence in the general population. Initial chapters cover the anatomy and physiology of the frontostriatal system, and the distinction between neurodegenerative and neurodevelopmental disorders, while the final chapter offers an integrative interpretation and comparison. The result is a unique, up-to-date, and wide-ranging discussion of these disorders that draws upon biology, genetics, neuropsychology, neuropathology, neuroimaging, and clinical presentation and treatment, and presents a controversial theoretical appraisal of the very concept of neuropsychiatric dysfunction. It will be of interest to advanced students, researchers and practitioners in neuropsychology, neuropsychiatry, psychiatry, and clinical psychology.