Etiology of Developmental Disorders: Good Science, Bad Science, and Pseudoscience

Abstract

Developmental disorders originate in infancy or early childhood, are associated with presumed or observed organic abnormalities, and have serious long-term physical and/ or psychological sequelae. Of particular interest here are two such disorders, mental retardation and autism. Purported causes range from genetics, early prenatal and/or postnatal exposure to toxins (including heavy metals), and recently, vaccinations. Single factors have often been claimed to be the cause of a developmental disorder, without regard to possible exacerbating or alleviating roles of other factors, including socioeconomic status. Unfortunately, professional and popular literature on both claimed causes and effective treatments has often been characterized by research and theorizing that is seriously flawed (bad science) or actively misrepresented (pseudoscience). The present paper critically reviews selected research on a few controversial issues concerning developmental disorders, particular mental retardation and autism, and emphasizes the role of low socioeconomic status.We must remember that children grow up only once [49].Otto Eiben devoted much of his career to studying the impact of economic conditions and change on children_s physical development. Pre-and early postnatal exposure to neurotoxins, such as infections, heavy metals, alcohol, and antiseizure drugs, may cause permanent central nervous system (CNS) damage (e.g., [1]), particularly among those living in impoverished areas or developing countries. In this paper, we summarize evidence about the effects of three environmental agents, emphasizing both controversies and socioeconomic issues. Owing to limitations of space, only a few sources can be cited.