THE DEFICIT SYNDROME IN SCHIZOPHRENIA: ASSOCIATIONS WITH HIPPOCAMPAL VOLUME AND PREFRONTAL CORTICAL THICKNESS

Abstract

up assessment which included the Positive and Negative Syndrome Scale (PANSS). Change in symptoms was defined as the difference in PANSS score at baseline and follow up (follow up – baseline). At baseline, all patientswere on antipsychoticmedication, themeandaily chlorpromazine equivalent (CPE) dose of the patient sample was 401. FreeSurfer software was used to generate intracranial volume, frontal cortical thickness, frontal cortical surface, and frontal cortical gyrification from the baseline MRI brain scans. Results: After controlling for age and intracranial volume, patients had a significantly thinner frontal cortex (means for controls and patients: 2.6 mm vs 2.4 mm, F=12.9, p<0.001, effect size (ES)= 0.13), decreased frontal surface (705.9 cm vs 696.8 cm, F=3.9, p=0.05, ES=0.05), and decreased frontal gyrification (3.0 vs 2.9, F=3.5, p=0.06, ES=0.05). Patients showed significant reduction in positive (t=10.1, p<0.001) and negative symptoms (t=5.5, p<0.001). Reduction in negative symptoms was positively correlated with baseline negative symptom severity (Pearson productmoment correlation coefficient (r)=0.6, p<0.001), meaning that a higher PANSS score at baseline was associated with more clinical improvement over time. Reduction in negative symptoms was positively correlated to frontal cortical thickness (r=0.5, p=0.003), meaning that greater clinical improvement was related with a thinner frontal cortex at baseline. This correlation remained significant after controlling for baseline negative symptom severity (r=0.4, p=0.003). Discussion: EOP in male adolescents is associated with a thinner frontal cortex. Frontal surface and gyrification may be less affected in EOP. Interestingly, our finding of a relationship between thinner frontal cortex and greater clinical improvement over time points to previous findings in longitudinal studies of grey matter changes in children, adolescents and adults with schizophrenia (Gur et al 1998, DeLisi et al 1998, Sporn et al 2003, Vidal et al 2006). In children and adolescents with early-onset schizophrenia, progressive loss of grey matter was correlated with greater clinical improvement (Sporn et al 2003) and less frontal grey matter was related to less symptoms at follow up (Vidal et al 2006). A full replication of these previous findings necessitates longitudinal MRI measurements, which is a future goal.