Reading deficits in schizophrenia contribute to underachievement

By Joanna Lyford, Senior medwireNews Reporter

People with schizophrenia display severe deficits in reading ability that are not captured in current routine clinical assessments, a study by US researchers indicates.

Writing in The American Journal of Psychiatry, the study authors say that reading deficits may be an important and remediable cause of the impaired education and occupational achievement associated with schizophrenia.

Daniel Javitt (Columbia University Medical Center/New York State Psychiatric Institute) and colleagues studied 45 people with schizophrenia, 19 people at clinical high risk for schizophrenia and 65 psychiatrically healthy control individuals.

All participants were assessed for reading ability, neurocognitive function, symptoms, socioeconomic status and sensory measures (auditory and contrast sensitivity).

The team found that schizophrenia patients displayed consistent and significant impairments in reading relative to healthy controls, with an overall large effect size. Patients showed particular impairments in the domains of reading fluency, phonological processing and visual reading.

Further analyses suggested that these reading impairments were largely explained by acquired (as opposed to neurodevelopmental) dyslexia. Three-quarters of the patients met criteria for dyslexia and 50% of patients read below eighth-grade level despite intact premorbid reading ability.

Reading deficits in the schizophrenia patients also correlated with failure to match parental socioeconomic achievement, over and above what would be explained by more general neurocognitive impairment.

Among the clinical high-risk cohort, overall reading ability was similar to that of healthy controls, although high-risk patients showed a significantly reduced reading rate. They also showed reduced rapid naming scores and had visual reading scores that were similar to those of schizophrenia patients.

Javitt and colleagues remark that the “ability to read is one of the most basic necessities for personal and occupational success in developed countries” and suggest people with schizophrenia may learn to read successfully but then develop reading deficits following the onset of illness. Such deficits are “far more severe than would be predicted based on general neurocognitive impairments”, they say.

They conclude: “The decline in reading ability from premorbid levels, which appears to occur during early stages of the illness, correlates highly with the failure to meet socioeconomic expectations, and may thus represent a remediable cause of persistent occupational disability in schizophrenia.”

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