In general, both may have some difficulty with cognition, with their memory, concentration, and so on. The depressed patient typically complains about their cognitive difficulty. The demented patient often does not complain. When performing a mental status examination, both may have impaired scores but the depressed patient will tend just not to answer tasks that they are finding difficult. Whereas the demented patient tends to answer and provide an erroneous, a wrong answer.
Depressed patients have some insight.
They have awareness that they are not thinking as well as they normally would be, whereas many demented patient s lack insight and are not aware of their cognitive deficits. Depressed patients are not disoriented. In pure and full form, depression can usually be distinguished based on standard diagnostic criteria. Many of the symptoms are overlapping or shared in common. Variety of combinations and overlaps are quite frequent.