In a substantial percentage of patients, mood disorders are accompanied by persistent neurocognitive impairment. Elderly patients with dementia often suffer from depression. Neurocognitive tests and imaging are increasingly used to complement diagnostics. Tests assessing memory, attention, executive functions, and visuospatial abilities might help to distinguish mood disorder patients who can be expected to develop dementia from those who will not. This review presents a summary of knowledge on neurocognitive profiles differentiating impairment in mood disorders and dementia. Ideas on pathophysiological causation and progression are translated into recommendations for patient management.