To the Editor: The report by Christopher and colleagues (1) in the February issue highlights the poor readability of informed consent forms for patients with mental illness. Their findings focused on the mismatch between the educational level of potential study participants and the actual grade level necessary to read the text. They reviewed consent forms for 154 studies and found that overall mean readability ranged from grade level 12 to 14.5, yet only one-third of potential research participants had actually graduated from high school. Although they acknowledge the limitations of their methodology, their results coincide with those of other studies that have found low levels of literacy in psychiatric settings and disparate reading levels and educational attainment (for example, three to five grade levels below achieved grade) as well as poor reading comprehension among individuals with schizophrenia (2,3).
We recently reported similar findings (4), noting that reading performance on the Nelson Denney Reading Test among 19 participants with schizophrenia indicated significantly reduced grade-equivalent reading comprehension scores (8.9±5.0 grade level) compared with years of education completed (12.4±2.3 years), with the mean difference being 3.4±3.8 years (paired t=3.9, df=18, p=.001). In contrast, ten individuals in a control group who did not have schizophrenia showed no significant difference between education level completed (15.2±.85 years) and reading ability (15.2±3.4 grade level); a significant group-by-diagnosis interaction was found (F=5.51, df=1 and 27, p=.003).
In addition, we found that approximately 50% of our patient group met criteria for dyslexia, depending on the diagnostic model. We also observed a strong relationship between reading deficits and more basic visual disturbances, particularly impaired magnocellular processing. Thus not only do patients with schizophrenia achieve fewer years of education, but their illness also produces a syndrome similar to dyslexia, which causes them to read, as a group, substantially below their achieved grade level. Our findings are consistent with follow-back studies, such as those by Fuller and colleagues (5), that show a decline in standardized reading score performance between grades 8 and 11 among individuals who later develop schizophrenia.
We agree with Christopher and colleagues that deficits in educational achievement should be fully appreciated when written consent forms are designed. We would like to highlight, however, that reduced educational achievement may be only a portion of the difficulty when it comes to interpreting written materials in schizophrenia and that adjustments should be made not only with regard to level of language complexity but also with regard to the actual physical layout of materials, to take into account levels of disability among individuals with schizophrenia.
Dr. Revheim is a research scientist-psychologist in the Program in Cognitive Neuroscience and Schizophrenia at the Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York. Dr. Javitt is the director of the program and professor in the Department of Psychiatry, New York University School of Medicine, New York.
Christopher PP, Foti ME, Roy-Bujnowski K, et al: Consent form readability and educational levels of potential participants in mental health research. Psychiatric Services 58:227—232, 2007
Sentell TL, Shumway MA: Low literacy and mental illness in a nationally representative sample. Journal of Nervous and Mental Disease 191:549—552, 2003
Hayes RL, O'Grady BM: Do people with schizophrenia comprehend what they read? Schizophrenia Bulletin 29:499—507, 2003
Revheim N, Butler PD, Schechter I, et al: Reading impairment and visual processing deficits in schizophrenia. Schizophrenia Research 87:238—245, 2006
Fuller R, Nopoulos P, Arndt S, et al: Longitudinal assessment of premorbid cognitive functioning in patients with schizophrenia through examination of standardized scholastic test performance. American Journal of Psychiatry 159:1183—1189, 2002