Although mainstreaming in education has been shown to provide benefits, there are also disadvantages to the system.
Tradeoff with non-disabled students' academic education: One potentially serious disadvantage to mainstreaming, is that a mainstreamed student may require much more attention from the teacher than non-disabled students in a general class. Time and attention may thus be taken away from the rest of the class to meet the needs of a single student with special needs. The effect that a mainstreamed student has on the whole class depends strongly on the particular disabilities in question and the resources available for support. In many cases, this problem can be mitigated by placing an aide in the classroom to assist the student with special needs, although this raises the costs associated with educating this child.
Harm to students with disabilities' academic education: Parents fear that general education teachers do not have the training and skills to accommodate special needs students in a general education classroom setting. However, professional training and supportive services can usually address these concerns. Some research has suggested teachers who are not aware of—and later may choose not to adopt—modifications needed for students with special needs are also more resistant to having these students in class. This can lead to regression of the students with disabilites as well as overall decreased classroom productivity.
Social issues: Compared to fully included students with disabilities, those who are mainstreamed for only certain classes or certain times may feel conspicuous or socially rejected by their classmates. They may become targets for bullying. Mainstreamed students may feel embarrassed by the additional services they receive in a regular classroom, such as an aide to help with written work or to help the student manage behaviors. Some students with disabilities may feel more comfortable in an environment where most students are working at the same level or with the same supports.
Costs: Schools are required to provide special education services but may not be given additional financial resources. The per-student cost of special education is high. The U.S.'s 2005 Special Education Expenditures Program (SEEP) indicates that the cost per student in special education ranges from a low of $10,558 for students with learning disabilities to a high of $20,095 for students with multiple disabilities. The average cost per pupil for a regular education with no special education services is $6,556. Therefore, the average expenditure for students with learning disabilities is 1.6 times that of a general education student.
Careful attention must be given as well to combinations of students with disabilities in a mainstreamed classroom. For example, a student with conduct disorder may not combine well with a student with autism, while putting many children with dyslexia in the same class may prove to be particularly efficient.
Special consequences for deaf students: Deafness is a low-incidence disability, which means that a deaf child will often be the only student in the classroom with hearing loss. This leads to a special set of issues in the mainstream classroom. While students with other disabilities may experience isolation and bullying by their non-disabled peers, they often share a common language. This is not the case for deaf students. Very few people in the mainstream academic setting know sign language, which means the communication barrier is large and can have negative effects on both academic achievement and social development.
Social skills are key to a child’s healthy development and later success as an adult. Although many studies find good academic results for deaf children placed in a mainstream classroom, research also shows that mainstreamed deaf children experience higher degrees of isolation and psychological problems in comparison to deaf students who associate with other deaf peers. In order for friendships to form, communication is a necessity. For deaf children unable to use effective communication methods with the people around them, the difficulty in acquiring new friendships typically leads to isolation and a decrease in self-esteem. A study of preschool children showed that hearing preschoolers did not appear to adjust how they communicated with deaf children. Instead, they continued to use simple speech, which was effective with hearing, but not deaf, partners. This shows the isolation of the deaf child, and discredits the idea that the hearing and deaf child's communication skills will be enhanced by interaction with one another. In many cases, hearing children do not understand what it means when another child is deaf. This leads to frustration when a deaf child’s speech is not clear or when the deaf child asks for continuous repetition. Communication strategies that are culturally acceptable to the deaf child, such as banging on a table or physically touching another person, can also cause the deaf child to be rejected by his or her peers because such behaviors are not always considered acceptable in mainstreaming hearing culture. Research has suggested that the placement of a deaf child in special schools or classes may be more desirable for deaf students than for those with other disabilities. This is primarily because of the greater social benefits for the students.
The residual knowledge that hearing children can access is often lost on deaf children. A hearing child can listen in on adult conversations, TV, radio and the news to learn things that are not specifically taught or told to them. This is not the case with the deaf child, who, in a hearing environment, can only learn what is directly communicated to them. This often leads to gaps in general knowledge, which can be both harmful to academic success and social interactions.
The effect of mainstreaming on Deaf culture is also a key issue for Deaf culture advocates. The rate of children enrolled in residential schools for the deaf is declining, as many hearing parents send their child to a mainstream school in hopes of preparing their child for life in the hearing world. In the past, Deaf schools and clubs served as the center for Deaf culture. Traditions, stories, and values developed and were fostered in these settings, but because of the low incidence of deafness, this same environment cannot be duplicated in the mainstream setting. Aside from the decreased socialization of a deaf child in a hearing school, Deaf community advocates also worry that the disappearance of residential Deaf schools will lead to a weakening of Deaf culture and of the community.