Language lateralization in female patients with schizophrenia: an f MRI study I.E.C. Sommer * , N.F. Ramsey, R.C.W. Mandl, R.S. Kahn Department of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands Received 22 December 2001; accepted 20 April 2002 Abstract Gender differences in schizophrenia are among the most consistently reported findings in schizophrenia research. However, the biological substrate underlying these gender differences is still largely unknown. Differences in language lateralization between men and women may underlie some gender differences in schizophrenia. In previous functional imaging studies, language lateralization was found to be decreased in male schizophrenia patients as compared to healthy males, which was due to enhanced language activation of the right hemisphere as compared to the healthy males. It could be hypothesized that decreased language lateralization in schizophrenia is gender specific, i.e. decreased lateralization in male patients and normal lateralization in female patients. To test this hypothesis, language activation was measured in 12 right- handed female patients with schizophrenia and 12 healthy females, and compared to findings in 12 male patients and 12 male controls of an earlier study. Language lateralization was significantly lower in the female patients (0.44) as compared to the female controls (0.75), which was due to increased activation of the right-sided language areas (patients: 19 voxels; controls: 8 voxels), while left hemisphere activation was similar in patients and controls. When these data are compared to the male patients and controls, both patient groups had lower lateralization than their healthy counterparts, but there was no difference between male and female patients. In both sexes, decreased lateralization resulted from increased right hemispheric language activation, which suggests a failure to inhibit nondominant language areas in schizophrenia. These findings indicate that lower language lateralization in women is not likely to underlie gender differences in schizophrenia. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Language lateralization; Schizophrenia; fMRI 1. Introduction As is well known, gender is an important factor in schizophrenia since differences in age at onset and course of schizophrenia between male and female patients are among the most consistent findings in schizophrenia research (Leung and Chue, 2000). The most striking gender difference is the age of onset (first appearance of psychotic symptoms), which is typically around 5 years later in females (Jablensky et al., 1992). Secondly, symptom profile is different between the sexes, with men having more negative symptoms and women having more paranoid psycho- sis and more affective symptoms (World Health Organization 1973, 1975). Thirdly, male patients are 0920-9964/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. doi:10.1016/S0920-9964(02)00300-6 * Corresponding author. Tel.: +31-30-2508352; fax: +31-30- 2505443. E-mail address: I.Sommer@azu.nl (I.E.C. Sommer). www.elsevier.com/locate/schres Schizophrenia Research 60 (2003) 183 – 190