Subcortical volumes, frontal cortical thickness, and pro-inflammatory cytokines in schizophrenia versus methamphetamine-induced psychosis

Abstract Background and Hypothesis Clinical features of schizophrenia and methamphetamine-induced psychosis (MAP) have significant overlap. Schizophrenia is associated with alterations in subcortical volumes and cortical thickness and pro-inflammatory cytokines, that may correlate with clinical features. However, analogous work on MAP is lacking. We hypothesise decreased frontal cortical thickness, amygdala and hippocampal volumes in schizophrenia and MAP compared to controls, with increased basal ganglia in schizophrenia compared to MAP. Study Design Participants included n=36 schizophrenia, n=27 MAP and 32 age- and sex-matched healthy controls. Diagnosis and symptom severity were determined with the Structured Clinical Interview for Axis I Disorders, and the Positive and Negative Syndrome Scale, respectively. Structural T1-weighted images were acquired using a 3-Tesla magnetic resonance imaging scanner. Serum peripheral cytokine concentrations were measured using a multiplex bead array. Study Results Schizophrenia and MAP participants showed decreased left amygdala volumes and frontal cortical thickness compared to controls. Schizophrenia participants had increased bilateral caudate, putamen, and nucleus accumbens (NAcc) volumes compared to controls, and greater right globus pallidus and NAcc volumes compared to MAP. Decreased left amygdala volumes and frontal cortical thickness were significantly associated with longer illness duration in schizophrenia and methamphetamine use in MAP. No significant differences were found in cytokine levels between groups or associations with neuroimaging measures. Conclusions This study highlights overlaps and differences in the psychobiology of schizophrenia and MAP.The novel discovery of increased globus pallidus and NAcc volumes in schizophrenia compared with MAP may show important distinctions in the neurobiology between these two conditions.