Depression is a common disorder, affecting approximately one in ten of the population at some time in their lives. The nature and extent of such changes, however, is less clear, and their specificity to mood disorder, their existence before the onset of affective symptoms, their etiology and their relation ship to underlying neuroanatomical abnormalities remain poorly understood. Our objective is to present a comprehensive review of the existing neuropsychological literature on bipolar affective disorder, mayor depression and the differential diagnosis between geriatric depression and the depression as early symptom of Alzheimer's disease. The most critical neuropsychological assessment to study this patients will be discussed. Depression is associated with dysexecutive syndrome which correlate with fronto subcortical diseases. Cognitive impairment include attention disorders, memory difficulties type forgetfulness and executive dysfunction (planning and executions of complex behaviors, monitoring of performance, feedback, decision making etc). Cortical neuropsychological profile in a depressive patients represent Alzheimer's disease associate. Neuropsychological assessment is useful to detect both different cognitive profiles (Cortical vs Subcortical).