Prelingual deafness has multiple and far reaching consequences for the development of language, cognition and the psychosocial dimension. Almost one of a thousand of the population is affected. Barriers in communication limit access to knowledge and participation in society. The use of sign language connects deaf people socio-culturally. This review shows discrepancies between high prevalence rates of mental health disorders with complex psychiatric challenges and barriers to mental health care. The UN convention on the rights of persons with disabilities obliges to counteract these discrepancies. Services with specialised signing professionals and the use of interpreters can improve access to mental health care.