LONDON, Oct 3: The behaviour of children with disabilities and learning difficulties often worsens when they start school, research suggests.
The Millennium Cohort Study analysis suggests children with disabilities can become more hyperactive and have difficulty getting on with classmates.
It urges more stringent anti-bullying strategies in schools.
Disabled children can struggle on "multiple fronts" at school said co-author Prof Lucinda Platt.
The researchers from the Institute of Education, the London School of Economics and the National Children's Bureau, analysed information on some 6,371 children in England, born in 2000 and 2001, who are being followed by the Millennium Cohort Study.
They compared children without disabilities with children with a number of developmental, learning and health problems.
These included children with long standing limiting illnesses such as asthma and those with special educational needs - such as hearing loss or learning difficulties.
The Millennium Cohort Study records information from parents on children's emotional, relationship and behavioural issues at the ages of three, five and seven.
The researchers were able to track the emergence of any problems and identify differences between the groups.
Children with long standing illnesses and learning difficulties were more likely to display hyperactive behaviour, to have difficulties getting on with other children and to have emotional problems.
They found these traits often became become more pronounced between the ages of three and seven.
"Our findings suggest that some early school environments may exacerbate behavioural problems for disabled children in ways that cannot solely be solved by learning support - because the underlying issue is behavioural rather than cognitive," say the authors.
Prof Platt, of the London School of Economic Department of Social Policy, said: "School is not the easiest environment and if you have other things to struggle with it can be very difficult.
"Other children adjust and their behaviour improves - but this is often harder for children with other challenges", Prof Platt told BBC News.
The authors cite previous research which suggests children with disabilities and learning difficulties are more prone to being bullied. They urge schools to adopt "more stringent anti-bullying strategies for those identified as different".