[Dementia-depression: how are they related? From depressive pseudodementia to pseudodepression in dementia].

Dementia and depression are among the most frequent and disabling conditions in the elderly. The prognosis of depression is similar in young and elderly patients; however, treatment can be more risky in the latter. Incorrect diagnosis of dementia as well as therapeutic relentlessness should be avoided. An attempt is made to clarify the ways dementia and depression can combine. The reality of pure depressive pseudodementia seems doubtful. Depression can worsen a dementia. Cognitive dysfunction can be observed in depression, though it is difficult to estimate the extent and the meaning of this association. Patients with very mild dementia are often referred for a depression, which is ruled out by careful examination. There is no simple mean to differentiate dementia from depression. The proper way remains to perform a strict clinical, neuropsychological and psychiatric examination.