Relevance for child and adolescent psychiatry

The first reported case of develop mental dyslexia appeared in the British Medical Journal in 1896. Dr Pringle Morgan, a general practitioner, described a 14-year-old boy named Percy, who, despite being ‘bright and of average intelligence in conversation’, had been unable to learn to read. Specimens of Percy’s writing show many spelling errors characteristic of dyslexia (such as ‘carlfuly’ for ‘carefully’, ‘pag’ for ‘peg’ and ‘Precy’ for ‘Percy’). Morgan pointed out that Percy could read numbers but had difficulties with written words. For example, he could discern the numeral 7 but not the word seven (Morgan 1896). Hinshelwood (1907) later called the condition ‘congenital word blindness’ The word dyslexia comes from the Greek dys-, broadly denoting difficultly or inadequacy, and lexis, meaning word. A number of terms have been used to describe dyslexia. In the psychiatric classifications ICD–10 (World Health Organization 1992) and DSM–IV (American Psychiatric Association 1994) it is called ‘reading disorder’. In ICD–10, this is classified under ‘Specific developmental disorders of scholastic skills’; in DSM–IV, it comes under ‘Learning disorders’. In the UK, the word dyslexia has not been popular in educational services (where it is most commonly encountered), and the term ‘specific learning difficulties’ is used in preference. Psychologists, who have carried out most research in this area, also tend to use the latter term. Other descriptions include ‘specific reading disability’, ‘reading disability’ and ‘reading retardation’. I use the word dyslexia as it has become etched in the minds of the public and professionals and provides a familiar shorthand for describing the condition. Over the past 40 years there has been a vast amount of research into reading acquisition and reading difficulties. In fact, dyslexia has been one of the most intensely studied subjects in developmental psychology. As a result, a massive amount of literature has accumulated that has helped us better understand the nature of the core deficits seen in dyslexia, their aetiology and clinical features.