Homocysteine (Hcy) is studied in relation to gender dependent schizophrenia in young males and to affective disorders in females. In relation with Hcy also the level of Vit.B12 and folic acid is investigated as they have ability to decrease the level of Hcy essentially.

The aim of our study is to get information about serum level of Hcy, Vit.B12 and folic acid in patients with schizophrenia's spectrum, autism, mood disorders and mental retardation and their possible link.

In the study 91 patients of Children's Psychiatric Hospital with above-mentioned diagnosis were involved, 37 of them with schizophrenia's spectrum disorders. Patients were selected according to their diagnosis (in line with ICD-10) and current clinical state. Each diagnosis and clinical state 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 among diagnosis, severity of disease and level of Hcy was r = -0.401 (p < 0.01). It was found out that the level of Hcy was the highest in 14 schizophrenic patients with acute condition and adverse course of disease.

First obtained data are indicative of potential link among the level of Hcy and schizophrenia and its severity, thereby it allows advancing hypothesis that Hcy can be as one of risk factors of schizophrenia.