Depression is one of the most common psychiatric disorders and, according to epidemiological studies, affects more and more people regardless of gender, age and education. Even in 30-50% of patients may show features of drug resistance, i.e. despite antidepressants in appropriate doses, it is not possible to achieve remission of symptoms for a sufficiently long time.  

Knowledge of the etiology of depressive disorders is growing, but many researchers are still working to elucidate their causes and construct new therapeutic approaches targeting specific pathophysiological mechanisms. We now know that dysregulation of neurotransmitters such as serotonin, dopamine or norepinephrine is not the only mechanism of depressive symptoms. The results of the study indicate that the central point in the pathophysiology of depression may be a disruption of the glutaminergic system, which is responsible, among other things, for regulating the excitation and inhibition of the activity of brain regions key to the occurrence of affective symptoms. The neurobiological basis of depression, including the associated cognitive deficits, may be considered dysfunctions in brain areas such as the prefrontal cortex, the cingulate cortex, the insula, the hippocampus and the amygdala.