The nosologies founded by Kraepelin (Psychotic Disorders) and Freud (Neurotic Disorders) still remain actual in categories F20-29, F30-39 and F40-49 of the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10). The psychopathological mechanisms observed in classic disorders are shared with disorders considered in other categories regarding recognized etiologies (F10-19), ages of onset (F90-98), symptoms as precocious and enduring traces (F60-69) or specific symptoms (F50-59). Each classic pathology and its psychopathological mechanisms may be prototypical for a specific nosological spectrum that includes diseases which seem different at first glance. Accordingly, based on the combined knowledge of psychopathology and neurosciences, we assume that it is possible to conceive a more logical, rational and simpler way of organizing psychiatric nosology based on different psychopathological mechanisms emerging from five major questions:

1. 1. does the patient recognize his territory? (Dementia and delirium spectra),

2. 2. does the patient accurately recognise himself and the other? (Schizophrenic vs. autistic spectra),

3. 3. does the patient conserve his synchronicity with environmental and interpersonal rhythms? (Manic and depressive spectra),

4. 4. how does the patient feel about and react to threatening experiences? (Phobic vs. paranoid spectra), and

5. 5. how does the patient behave towards appetizing experiences? (Obsessive vs. Dissociative spectra).

We also discuss the relationship of these major questions with the encephalic stages (telencephalon, diencephalon, mesencephalon, and rhombencephalon).