Memory is a mental process that consists of recognition, retention, recollection and recall. The frontal lobe, thalamus, medial temporal lobe and limbic system of the brain are involved in memory activities. Memory function is more affected by attention and emotion in patients with depression. Patients have markedly diminished memory, as evidenced by decreased short-term and instantaneous memory capacity, difficulties with free association, gross quality recall, and recognition. The patient’s long-term memory remained more intact throughout the course of the disease. The cerebral cortex, hippocampus, amygdala and cerebellum are most likely to be involved in memory trace formation, and the hippocampus in particular has an important role in learning and memory activities. sheline et al. reported that decreased declarative verbal memory in depression was associated with hippocampal volume atrophy. In depressed patients, psychomotor speed is slowed and free recall is difficult. Ilsley suggested that patients have smooth information encoding processes but specific processes of recall and recollection are impaired, which corresponds to retrieval and extraction difficulties in information processing theory. Regression analysis also confirmed a correlation between the degree of psychomotor retardation and free association in patients. Patients with major depression performed worse on the Wechsler Adult Memory Scale (WMS) in regeneration, association, and comprehension than patients with moderate depression, suggesting that the severity of the condition correlates with the degree of deficits in recognition and gross recall in information processing.