No progression of the alterations in the cortical thickness of individuals with schizophrenia-spectrum disorder: a three-year longitudinal magnetic resonance imaging study of first-episode patients

Abstract

Background: Cortical thickness measurement offers an index of brain development processes. In healthy individuals, cortical thickness is reduced with increasing age and is related to cognitive decline. Cortical thinning has been reported in schizophrenia. Whether cortical thickness changes differently over time in patients and its impact on outcome remain unanswered.

Method: Data were examined from 109 patients and 76 healthy controls drawn from the Santander Longitudinal Study of first-episode schizophrenia for whom adequate structural magnetic resonance imaging (MRI) data were available (n = 555 scans). Clinical and cognitive assessments and MRIs were acquired at three regular time points during a 3-year follow-up period. We investigated likely progressive cortical thickness changes in schizophrenia during the first 3 years after initiating antipsychotic treatment. The effects of cortical thickness changes on cognitive and clinical variables were also examined along with the impact of potential confounding factors.

Results: There were significant diagnoses × scan time interaction main effects for total cortical thickness (F 1,309.1 = 4.60, p = 0.033) and frontal cortical thickness (F 1,310.6 = 5.30, p = 0.022), reflecting a lesser thinning over time in patients. Clinical and cognitive outcome was not associated with progressive cortical changes during the early years of the illness.

Conclusions: Cortical thickness abnormalities do not unswervingly progress, at least throughout the first years of the illness. Previous studies have suggested that modifiable factors may partly account for cortical thickness abnormalities. Therefore, the importance of implementing practical actions that may modify those factors and improve them over the course of the illness should be highlighted.

Keywords: Clinical assessment; cortical thickness; first-episode psychosis; longitudinal studies; schizophrenia; structural magnetic resonance imaging.