Comparing Copper Serum Level and Cognitive Functioning in Patients With Schizophrenia and Healthy Controls

Introduction: The altered serum profiles of several trace elements have been reported in Schizophrenia (SCZ). This study was designed to elucidate whether the serum levels of Copper (Cu) and Magnesium (Mg), the two essential trace elements which contribute to neurotransmitter transmission, are altered in patients with SCZ. We also investigated whether there is an interrelation between cognitive functioning and the serum levels of Cu and Mg.

Methods: Sixty patients with SCZ and 30 healthy controls participated in this study. The patient group was divided into the following: i) early patients (n=35, ≤5 years of illness initiation), and ii) chronic patients (n=25, ≥5 years of illness duration). The serum levels of Cu and Mg were measured by atomic absorption spectroscopy and ion-selective electrode potentiometry, respectively. To assess cognitive abilities, a Persian adaptation of the Brief Assessment of Cognition in Schizophrenia (BACS) was administered.

Results: The present research results revealed significantly higher Cu serum levels in both patient groups [early patients (M=94.6), chronic patients (M=97.5)], compared to the controls (M=71.0) (P<0.001); however, no significant difference was observed among the study groups for Mg [patients with the recent onset (M=2.0), chronic patients (M=2.0), and controls (M=1.9)] P=0.1. While the serum Cu profile of healthy individuals revealed a negative correlation with working memory (r=-0.42, P=0.02), and executive functioning (r=-0.40, P=0.03), no significant correlation was observed between Cu serum levels of patients and BACS cognitive domains.

Conclusion: findings suggested that the high Cu serum concentration might impact the cognitive decline in healthy individuals; however, no significant correlation was observed in the Patients; i.e. most likely because cognition is severely impaired in SCZ. Additional studies examining trace elements in drug-naïve patients with SCZ are required.