Background: Psychotic disorders are characterized by structural brain changes, such as reduced cortical thickness. Yet, it is unclear whether these changes arise from primary illness factors, such as symptom severity, or from secondary effects, such as medication. This study utilizes the Human Connectome Project for Early Psychosis to evaluate cortical thickness in individuals with early-course psychosis, and the potential relationship to medication, symptom severity, and affective/nonaffective psychosis diagnosis.
Methods: Participants included 159 individuals with early psychosis (EP) and 67 (HCs) from HCP-EP data. Regions of interest (ROI) from the Desikan-Killiany atlas were derived from T1-weighted MR images quality controlled and processed using FreeSurfer(v7). Linear regressions were used to compare ROI thickness between EP and HC groups after controlling for age, sex, handedness, scanner, and estimated total intracranial volume. Pearson correlations were used to assess the relationship between ROI thickness and current antipsychotic medication intake. Secondary analyses examined relationships between cortical thickness and symptom severity (PANSS), and affective/nonaffective psychosis diagnosis.
Results: After FDR correction, EP subjects displayed significantly reduced cortical thickness in the left superior temporal (STG) (F(7, 218)=8.90, FDRp=0.05) and left middle temporal gyri (MTG) (F(7,218)=5.21, FDRp=0.02) compared to HCs. Lower cortical thickness in both regions correlated with higher current medication dose in EP individuals (STG: r(127)=-0.227, FDRp=0.009, MTG: r(127)=-0.310, FDRp= 0.0006). There was no significant relationship between cortical thickness in these regions with PANSS scores, or affective/nonaffective psychosis diagnosis after FDR correction.
Conclusions: Our analysis confirms prior reports of reduced cortical thickness in left-hemispheric temporal cortical regions. Crucially, these deficits were associated with current medication dose and not with illness-related factors, raising important implications for understanding the early structural changes in the brain linked to the presence and treatment of psychosis.
Emily Johns, A.B., Maria A. Di Biase, Ph.D., Johanna Seitz-Holland, M.D., Ph.D., Sylvain Bouix, Ph.D., Michael J. Coleman, M.A., Marek Kubicki, M.D., Ph.D., Ofer Pasternak, Ph.D., Raquelle I. Mesholam-Gately, Ph.D., Kathryn Eve Lewandowski, Ph.D., Daphne Holt, M.D., Ph.D., Matcheri S. Keshavan, M.D., Dost Ongur, M.D., Ph.D., Alan Breier, M.D., Martha E. Shenton, Ph.D., Amanda E. Lyall, Ph.D.
Martha E. Shenton, PhD