Aaron T. Beck's cognitive model of depression became the basis for the analysis of cognitive factors as significant correlates and predictors of depression. Psychological mechanisms of depression related to the depressive cognitive triad, the specificity of cognitive schemas and errors in cognitive processing determined the directions of further research on depression. The presented analysis of selected studies confirms and extends Beck's assumptions about the role of cognitive factors in the development and maintenance of depressive symptoms. The analysis of psychological, neuroimaging and biochemical studies provides a broader perspective of understanding both the etiology and mechanisms that sustain the symptoms of depression. The development of neuroimaging research has broadened the knowledge about the brain mechanisms of depression - the presented research combine the theoretical constructs of the cognitive concept of depression with the characteristics of the activity of brain structures and their functional connections. The following conclusions seem to be particularly important for clinical practice: 1) impairment of the cognitive inhibition function in depression reduces the control of negative automatic thoughts - strengthening working memory is important; 2) different brain mechanisms for processing rewards and punishments in people suffering from depression and in healthy people explain the formation of self-esteem - this knowledge can be an important element of psychoeducation in therapeutic work; 3) neuroimaging studies indicate neuronal correlates of cognitive distortions observed in depression - for further research on depression, it would be particularly important to monitor changes in brain activity in the course of its treatment.