According to the Krepelin approach, depressive spectrum disorders are divided into:

· Endogenous depression;       

· Dysthymic disorder;       

· Somatized depression;       

· Pseudodement depression;       

· Depression within the framework of schizophrenia and schizoaffective psychosis;       

· Depression with alcoholism;       

· Depression with substance abuse.       

All these conditions are classified as affective spectrum disorders, which is confirmed by the effectiveness of thymoanaleptic therapy. 

But in recent years, antidepressants have begun to be used for diseases that are not based on an affective component: bronchial asthma, irritable bowel syndrome, neurodermatitis, OCD, panic states, and habit disorder.

The mechanism of drug effectiveness is not entirely clear. Only the serotonergic component of the drug action mechanism was noted . The classification of diseases of the depressive spectrum and their treatment based on molecular markers has not yet been developed. Therefore, the choice of drugs is based on the syndromic , nosological principle and the severity of symptoms. According to him, drug therapy is necessary for endogenous depression with unipolar and bipolar course. And the treatment of depression against the background of schizophrenic psychosis is supplemented with antipsychotics. Somatic depression requires pathogenetic therapy, and only in the last place is the appointment of psychotropic drugs.

Dysthymia and neurotic depression are treated with antidepressants in conjunction with tranquilizers. Thus, therapeutic approaches to treatment are based on a nosological framework. In the 21st century, this approach hinders the development of not only psychopharmacology, but also the disclosure of the etiology and pathogenesis of depression. The accumulated knowledge in the field of genetics of depressive disorders, interaction of biological factors, imbalance of neurotransmitters , neuroimaging will allow changing both the classification of depression and their treatment with the help of pharmacological drugs.