In this book, Jay Joseph presents an up-to-date, thoroughly documented, and much-needed critical appraisal of schizophrenia genetic research. His findings have important implications for psychiatry, behavioral genetics, and the social and behavioral sciences in general. For generations, there has been a belief that schizophrenia has genetic causes. Although this thesis continues to be the basis of the treatment, the truth is that it has never been satisfactorily demonstrated. Most of the diagnosed patients did not have parents with this disorder. In addition, numerous studies have recently emerged that link schizophrenia with traumatic experiences in childhood and with social factors such as poverty, racism or migration stress. In this context, psychologist Jay Joseph focuses on the methodological shortcomings and questionable assumptions of previous schizophrenia studies on families, twins, and adoption. The author puts the influential Danish and American adoption studies of the 1960s and 1990s under the microscope, taking readers on a journey through massively flawed, biased, and environmentally confusing studies that have been presented in standard textbooks in a deceptive way.