Social inclusion of pupils with severe learning difficulties is making teachers feel failures, delegates said.
Classroom dynamics were upset while teachers faced constant skills updating because of the different problems that were now brought into their classes.
Heather McGrattan, East Dunbartonshire, said: "We cannot have a class teacher with five other adults in the classroom to manage. Social inclusion is the right way forward but every child is special, not just the one with special additional needs."
She believed any co-ordinated support plan had to look at the dynamics of the class and how pupils would affect it. "We end up feeling we're failing every child in the class to whom you want to give five minutes peace and quiet without disruption," she said.
Willie Hart, Glasgow, said "time and time again" the minimum criteria for taking pupils with additional needs were not met by local authorities.
"When a teacher is confronted by little or no warning, with absolutely no training and with no SEN auxiliary and another 32 children in the class, I'm not surprised they throw their hands up in despair and ask 'What am I going to do?'," Mr Hart said.
Such common scenarios did nothing for integration and the attitudes of other pupils to those with additional needs. "Everyone ends up scunnered not just with their actual experience but the very positive ambition that lies behind social inclusion," he said.
Anne Darling, Edinburgh, who had completed 13 years in an out-of-school unit and had never been assaulted, said the small, supportive environment allowed intensive work with a group of pupils who could not cope in mainstream. One teacher and one social worker were working with no more than 12 pupils. An educational psychologist and mental health worker were part of the team. "It works because it is well resourced," she said.
Sandra Mackenzie, South Lanarkshire, described the threats to special schools and the presumption of mainstreaming as "political correctness at its worst". Her own daughter had gone to a special school and benefited enormously, she said.