VIOLENT pupils are arriving in school "fuelled" by high-energy drinks and intent on causing disruption, teachers have warned.
And because of cuts to education budgets support staff are no longer available in sufficient numbers to deal with the problem.
Energy drinks contain high levels of caffeine and sugar and have already been associated with public health problems by the World Health Organisation.
Teachers from the Educational Institute of Scotland (EIS) went on to call for an increase in specialist provision such as sin bins, where aggressive pupils could be taken.
The issue was discussed at the annual general meeting of the EIS in Dundee where teachers warned the policy of inclusion was at breaking point.
Under the policy, which is supported by the United Nations, more pupils with additional support needs are taught in mainstream rather than special schools because it is seen as more inclusive and therefore better for society.
However, surveys have shown teachers are concerned the move has led to rising indiscipline and a negative impact on the education of other pupils.
A report by school inspectors in 2001 said in-school behaviour support units had allowed teachers to remove trouble-makers from the classroom without disrupting their education or that of their peers, but teachers said these facilities were being cut.
Susan Talboys from the union's Aberdeen branch, said so-called mainstreaming had put more pressure on teachers to put up with bad behaviour "or fear being branded a failure".
She said: "Pupils from homes that are chaotic and where there are no boundaries are arriving in school not in a fit state for learning.
"They may not have had a good night's sleep, they may not have had any breakfast and they often come to school fuelled up with high-energy drinks.
"For these pupils school is the only constant in their lives, but conforming to the boundaries is not the norm for them and bad disruptive behaviour leading to aggression and violence is an expression of their need. But that is not acceptable.
"All too often we concentrate on the rights of these pupils to be educated in school, but there appears to be less appetite to look at the rights of staff and other pupils who want to work and study in an environment that is free from unacceptable levels of aggression and violence."
She said such pupils needed specialist support and, for some, that meant being taught away from the mainstream school environment.
Jim Glen, from the Midlothian branch of the EIS, said some teaching staff "expected" to be violently attacked and even accepted it as part of their working lives "as if it had been written into their contracts".
Derek Ross, from the Aberdeenshire branch, added: "We embraced inclusion, but, with cutbacks, classroom support and additional teachers have been withdrawn from supporting the many pupils in our schools who exhibit challenging behaviour.
"We are not getting it right for these pupils or for the thousands of pupils whose lessons and learning are are disrupted. It is not appropriate for pupils with behavioural difficulties to be spending their days… sitting outside or inside a depute's office.
"Nor is it appropriate that other pupils education is disrupted and that their mental health and wellbeing are compromised by witnessing unpredictable and violent behaviours. We have a right to go home without feeling abused bullied and demoralised."
Nearly a quarter of pupils in Scottish schools are classed as having additional needs, but council cuts have seen a 10 per cent fall in specialist support staff in five years.