Cognitive symptoms in depression are associated with high distress, poor functional outcome and more relapses. Variability in cognitive deficits in depression is often reported, and may originate from numerous factors; one rarely examined factor is psychiatric history.

To assess the effects of depression and severe psychiatric history on old-age cognitive performance.

From a sample of non-demented participants (60+ years) in a population-based study receiving neuropsychological testing, three groups were formed based on information from the Swedish national inpatient register (1969-2005): current unipolar depression (ICD-10)/no psychiatric history (n=49), current unipolar depression/psychiatric history (n=16; F10-F45, F31-31.9 excluded), remission/history of mood disorders (n=35, F31-31.9 excluded). In addition, a group of healthy controls (n=98) was randomly selected.

Currently depressed participants without psychiatric history performed at a lower level compared to healthy controls in processing speed, attention, executive function, verbal fluency, episodic free recall and vocabulary. However, remitted participants performed at the same level as healthy controls, and outperformed currently depressed with psychiatric history in verbal fluency. No group differences were observed for short term memory, episodic recognition, general knowledge or spatial ability.

Currently depressed without psychiatric history consistently performed at the lowest level. The proportion receiving psychopharmacological treatment in this group was low, 6.1% compared to 56.2% and 37.1%, which may partially account for this finding. Additional factors potentially explaining why remitted participants and healthy controls perform at the same level cognitively will be examined. These findings may have important implications for preventing residual cognitive deficits in depression.