Schizophrenia
Adults with Asperger syndrome may be diagnosed as suffering from schizophrenia. The differential diagnosis of schizophrenia has been discussed elsewhere (J.K.Wing, 1978). The main difficulty arises from the fact that schizophrenia has been defined loosely by some and strictly by other workers.
If a loose definition of schizophrenia is accepted, based only on characteristics such as social withdrawal and speech disorder, then a case could perhaps be made for including Asperger syndrome in this group. As with schizoid personality, the question is whether doing so has any advantages. Poverty of social interaction and abnormalities of speech can have many different causes, so the diagnosis of chronic or simple schizophrenia tends to cover a variety of conditions having little in common with each other.
Careful observation of speech in Asperger syndrome discloses differences from thought blocking and the 'knight's move' in thought described by Bleuler (1911). In Asperger syndrome, speech may be slow, and there may be irrelevant or tangential replies to questions, but these problems are due partly to a tendency to become stuck in well-worn conversational grooves rather than to produce new ideas. Utterances are always logical, even if they are unrelated to the question, or originated from an unusual point of view. Thus one young man, when asked a general knowledge question about organised charities, said 'They do things for unfortunate people. They provide wheelchairs, stilts and round shoes for people with no feet'. There is a marked contrast between the vague woolliness of schizophrenic thought and the concrete, pedantic approach found in Asperger syndrome.
The term schizophrenia can be used more strictly. It can be confined to those who have, currently or in the past, shown the florid first-rank symptoms described by Schneider (1971). In this case, the differentiation of Asperger syndrome rests on accurate definition of the clinical phenomena. Unless they have a superimposed schizophrenic illness, people with Asperger syndrome do not experience thought echo, thought substitution or insertion, thought broadcast, voices commenting on their actions, voices talking to each other, or feelings that external forces are exerting control over their will, emotions or behaviour. The young man, L.P. (Appendix No. 2), when asked if he had such experiences, gave the matter long and careful thought and then said, 'I believe such things to be impossible'.
During clinical examination it is necessary to be aware that comprehension of abstract or unfamiliar concepts is impaired in Asperger syndrome. Those with the more severe form of the handicap may have a habit of answering 'yes' to any question they do not understand, this being the quickest way to cut short the conversation. Some may also pick up and repeat phrases used by other people, including other patients in a hospital ward, making diagnosis even more difficult.
....Finally, the relationship to schizophrenia of Asperger syndrome, autism and similar impairments can be reconsidered. Although they are dissimilar in family history, childhood development and clinical pictures, both groups of conditions affect language, social interaction and imaginative activities. The time of onset and the nature of the disturbances are different, but there are similarities in the eventual chronic defect states that either may produce. It is not surprising that autism and schizophrenia have, in the past, been confused. Progress has been made in separating them and it is important to continue to improve precision in diagnosis, despite the many difficulties met in clinical practice.
http://www.mugsy.org/wing2.htm