Brain morphological changes in affective disorders occur mainly in the fronto-limbic cortex, hippocampus and amygdala – the structures regulating emotional and cognitive functioning, as well as development of somatic symptoms in the course of disorders. The largest number of reports of structural changes in the cerebral cortex include the dorsolateral prefrontal cortex, the orbitofrontal cortex and the anterior cingulate cortex. The results of neuroimaging and sectional studies reveal changes in the volume of structures involved in the creation of neuronal circuits that affect development of mood disorders. Microscopic studies show changes in cell count, density, and morphology in these areas. Some of those changes are observed only in certain layers of the cerebral cortex. A valuable addition to this data are histochemical studies of neuronal survival markers, proinflammatory cytokines, trophic factors, and markers specific for particular cellular structures. The role of monoaminergic, GABA-ergic and glutamatergic neurotransmission is confirmed by the studies on concentration of neurotransmitters, their receptors and transporters. Some of the results correlate quantitatively with the type and severity of symptoms, duration of the disorder, as well as pharmacotherapy and nonpharmacological treatment.