For the studies, we have used 225 patients from Children's Psychiatric Hospital. 82 of all selection were with schizophrenia spectrum disorders, 27 patients with affective disorders and 116 patients came from control group.

Patients were selected according to their diagnosis (in line with ICD-10) and current clinical status. Each diagnosis and clinical status was coded depending on its severity and course of disease.

The level of Hcy was stated by isocratic HPLC system with fluorometric detection (Shimadzu LC-20, model RF-10AxL).

Correlation of Hcy concentration between schizophrenia's spectrum disorders and control group was r = -0.39 (p< 0.001; t = 22.99).

Mean level of Hcy was 11.94 μmol/L for patients with schizophrenia's spectrum disorders and 11.55 μmol/L for patients with affective disorders versus 7.47 μmol/L in control.

It has been found that the highest level of Hcy in the group of schizophrenia spectrum disorders has been seen in patients with episodic-recurrent course of disease, especially with pronounced affect. For the group with affective disorders the highest level was seen in patients with depressive symptoms with anxiety and mixed affective disorders (r = 0.58; p< 0.001; t = 12.77).

Obtained data are indicative of potential link among the level of Hcy and schizophrenia, and that the level of Hcy is inwrought with affective disorders and anxiety in the course of disease.