What are neurodevelopmental disorders?

The purpose of this review is to highlight the origin and evolution of the field of neurodevelopmental disabilities and describe the main construct(s) upon which the current classification of neurodevelopmental disorders is based.We address the following questions: Are neurodevelopmental disorders independent entities? Why is it desirable to understand the neurobiological substrate for these disorders? What new knowledge have we generated by leveraging advances in neuroscience, genetics, and neuroimaging? And finally, is the current construct, that is based on functional classification, still useful?As our biological understanding of brain-behavior disorders evolves, we ought to re-evaluate the current classification system and expand it into a multidimensional classification that takes into account behavioral profiles and underlying mechanisms.