Special Educational Needs (SEN) policy and practice in England and Wales currently relies on an authoritative and accurate diagnosis of need by professionals working in partnership with parents and children. Our analysis suggests there is a "continuum of disengagement" for children and young people with SEN. This will be used as a central theme to illustrate the disjuncture between SEN policy and practice. The continuum becomes apparent under the scrutiny of issues that arise during the diagnostic process. Identification of problems such as attention deficit hyperactivity disorder, dyslexia and dyspraxia lead to methods of intervention that can be identified as either preventative, counteractive or punitive. The ambiguity of the diagnostic process lies in the overlapping characteristics of these conditions. Referring to our research in the field of SEN provision in North Wales, this article explores the link between hidden disabilities, increasing disengagement and youth offending.