Abstract
Background: There is a high level of variance in the way patients with schizophrenia (SZ) respond to antipsychotic drugs (APD). As a result, clinicians typically choose treatment based on trial and error. There is a need to identify biomarkers to assist with the determination of treatment response early in the course of illness. Gyrification, potentially indicative of aberrant neurodevelopment, might provide such a biomarker. Using a longitudinal design, we seek to evaluate whether index of gyrification before treatment would be predictive of subsequent treatment response to APD.
Methods: Patients were treated for 6 weeks with an APD; treatment response was assessed using the Brief Psychiatric Rating Scale. We obtained T1-weighted images in 46 unmedicated SZ patients. Using a median split, they were divided into good and poor treatment responders. Whole brain segmentation was performed, and local gyrification indices (LGIs) were calculated from T1 images using FreeSurfer. Abnormalities in LGI associated with good and poor treatment response were examined using a general linear model with age and total intracranial volume as covariates. Monte Carlo simulation was used to correct for multiple comparisons (P < .05).
Results: Abnormalities in gyrification were similar in treatment responders and nonresponders when compared to healthy controls (HC) in the temporal cortex, insula, and rolandic operculum; however, the extent of hypogyria in superior frontal (including the medial wall) and temporal cortex were greater in nonresponders.
Conclusion: These results demonstrate that the level of cortical folding is predictive of treatment response. Furthermore, our findings are in agreement with those of Palaniyappan et al. (2013) who identified hypogyria in temporal cortex as more prominent in treatment nonresponders versus responders.