Letter

Reading Disability Goes Beyond Consent Forms

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.