Bilingualism and neuropsychiatric disorders

A range of psychotic manifestations (including auditory hallucinations, delusions, conceptual disorganization, anxiety, and depression) have been reported to occur in either one or all of a patient's languages. The reasons why one of the patient's languages may be more affected than others is investigated. Whether a particular language should be used in psychotherapy, and if so, which one, is also explored. The need for bilingual health professionals and the advantages and disadvantages of using interpreters are assessed. Different aspects of biculturalism (as distinct from bilingualism) and their various implications are examined. The possible effects of age and manner of second language appropriation are discussed. Differential symptoms in bilingual individuals with Huntington's, Parkinson's and Alzheimer's diseases are briefly reviewed. Parallels between bilingual aphasia and symptoms of psychoses and dementia are outlined. These various phenomena are considered within the framework of a neurolinguistic theory of bilingualism.