Trace elements concentrations association with schizophrenia symptoms; A cross-sectional study in Croatia.

Background: Significant inconsistencies exist in findings on association of bio-elements (BE) concentrations and schizophrenia. Hypothesis of this research was that different concentrations of BE are associated with different psychopathological schizophrenia symptoms.

Subjects And Methods: This cross-sectional study was performed from 2014 to 2016 at Psychiatric Hospital "Sveti Ivan" and University Psychiatric Hospital "Vrapče", Zagreb, Croatia, on the consecutive sample of 67 patients diagnosed with schizophrenia. BE concentrations were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) at the Institute for Medical Research and Occupational Health in Zagreb. Severity of schizophrenia symptoms was assessed on Brief Psychiatric Rating Scale (BPRS).

Results: After adjustment for all preplanned possible confounding variables, the first canonical correlation between BE and BPRS dimensions variates were statistically significant (Rc=0.73; P=0.006). The first pair of canonical variates is defined by BPRS negative dimension (and marginally by positive symptoms and lack of resistance), and copper (Cu), lead (Pb), lithium (Li) and cobalt (Co) (marginally by cadmium (Cd) and nickel (Ni)).

Conclusions: Concentrations of different BE are associated with different schizophrenia symptoms. Maximal correlation between BPRS and BE may be achieved with the weighted linear composite of negative schizophrenia symptoms and copper (Cu), lead (Pb), lithium (Li) and cobalt (Co).