Many children have a mixture of features from these two syndromes but do not fit neatly into either. The whole spectrum is defined by the presence of impairments affecting social interaction, communication and imagination, known as the triad of impairments. This is always accompanied by a narrow, repetitive range of activities. A range of other problems is also commonly found in association with the triad but the three basic impairments are the defining criteria. Diagnosis Diagnosis can be difficult, as there are no definitive medical diagnostic tests and the manifestations of the problems can occur at any level.
Some children are very disabled with low levels of functioning.
Others have superior intelligence with very high levels of skills in certain areas. Causes The exact causes of autism have not yet been fully established. It is, however, evident from research that autism can be caused by a variety of conditions affecting brain development, which occur before, during or after birth. Recent research indicates that genetic causes are very important, though the sites of the relevant genes have not been identified. Autism affects more males than females.