Specific developmental disorders in childhood and adolescence 

The term ‘specific developmental disorders’ includes a variety of severe and persistent difficulties in spoken language, spelling, reading, arithmetic, and motor function. Skills are substantially below the expected level in terms of chronological age, measured intelligence, and age-appropriate education and cannot be explained by any obvious neurological disorder or any specific adverse psychosocial or family circumstances. As the deficits are quite substantial, analogies were initially made to neurological concepts and disorders such as word-blindness, alexia, aphasia, and apraxia, thus giving rise to the notion that neurological deficits are the aetiological basis of these disorders. Since this could not be demonstrated, the next step was to define the disorders in a more functional way, taking into account not only psychometric testing but also psychosocial risk factors and the quality of schooling and education. Today, numerous findings support the validity of the diagnostic concept of specific developmental disorders. These disorders and pervasive developmental disorders have the following features in common (ICD-10): ♦ An onset that invariably appears during infancy or childhood. ♦ An impairment or delay in the development of functions that are strongly related to biological maturation of the central nervous system. ♦ A steady course that does not involve the remissions and relapses that tend to be characteristic of many mental disorders. Thus the term ‘specific developmental disorders’ reflects the fact that the deficits are circumscribed and relatively isolated against the background of an otherwise undisturbed psychological functioning.