*3.1. Study Participant Characteristics*

The sociodemographic and clinical characteristics of the examined group are presented in Table 1. The study included 40 individuals with schizophrenia (SZ group; mean age: 31 years old; 52.5% males) and 40 healthy volunteers as the control (HC group) (mean age: 29 years old; 37.5% males). There were no significant differences between the clinical and control groups in age, gender, and body mass index (BMI) (*p* > 0.05). The median of illness duration was 78 months, and the number of hospitalizations was two. In total, 95% of patients were taking antipsychotic medication. Most of the SZ group was treated with second-generation antipsychotic drugs (*n* = 36; 90%). Other patients (*n* = 2; 5%) received first-generation antipsychotic drugs, one of them together with an anticonvulsant drug. In total, five persons (12.5%) received first-generation treatment, 13 (32.5%) individuals took anticonvulsant medications, and six individuals (15%) received selective serotonin reuptake inhibitors (SSRIs). Two patients (5%) received benzodiazepines. Furthermore, 5% (*n* = 2) of the SZ group was antipsychotic-free due to medication nonadherence. The median modal doses of antipsychotic medication treatment were 15 mg of olanzapine equivalent [21]. The average severity of schizophrenia symptoms measured with the Positive and Negative Symptom Scale (PANSS) scale was 54 points (median) (a maximum score of 210 points).


**Table 1.** The characteristics of studied population.

PANSS—Positive and Negative Symptom Scale; SZ—schizophrenia; HC—healthy control; BMI—body mass index; SD—standard deviation; NA—not applicable; NS—not significant. The Mann–Whitney U-test was used.
