In bilingual people, impaired language may be an indicator of schizophrenia, new research suggests. Participants who were diagnosed with schizophrenia and spoke two languages had more speech impairments in their second language (L2) than in their first language. This included more incomplete sentences and repeated words.
Lead author Daria Smirnova, MD, PhD, Department of Psychiatry at Samara State Medical University in Russia, said, “We found that symptoms of schizophrenia were mostly represented in the second language.” Dr. Smirnova noted that speech impediments were not due to “incompetence of second language” since all participants were fluent. It could be due to the way people with schizophrenia process speech.
The researchers write in comparing the two languages spoken by individuals with schizophrenia “we hope to shed new light on the linguistic profile of the disorder, thus focusing on the crucial role of language in schizophrenic research.” For the study, researchers enrolled 60 Russian immigrants in Israel with schizophrenia and found that 10 spoke both Russian and Hebrew fluently.
After undergoing interviews conducted in both of their languages, the researchers found three linguistic markers occurred significantly more often in the second language than in the first. These included: syntax, lexical repetition, and exophoric reference, using a pronoun or word to refer to something/someone not named before.
Further research is needed, but Dr. Smirnova said if future studies show similar results, it may be helpful to train patients to construct and complete sentences more correctly in the second language causing them to use the left hemisphere of the brain more. “It will be very interesting to expand this to international research and compare languages, especially those that have been shown to use the right hemisphere more,” she said. “Also, perhaps including language criteria into diagnostic criteria for schizophrenia could be important.”