To assess cognitive function in older euthymic bipolar patients. To investigate the relationship between cognitive disorders and clinical features in this population.

We conducted a cross-sectional study during the period from August to November 2015. It included 34 stable bipolar outpatients, aged at least 65 years. We used the Montreal Cognitive Assessment (MoCA) to screen for cognitive disorders. Our patients were clinically euthymic, as checked by the Hamilton depression scale and the Young mania scale.

The sex ratio was 1. The mean age of our patients was 68.2 years. Most of them were married (82.4%), unemployed (55.8%), living in urban area (82.4%), had low educational level (58.8%) and low income (64.7%).

The majority was bipolar type 1 (67.6%). The most recent episode was manic in 55.9% of cases, including psychotic features in 50% of cases. Subsyndromal affective symptoms were noted between episodes in 23.5% of them. The average MoCA score was 23.6. Cognitive disorders were found in 61.5% of patients, who showed impairments across all cognitive domains. The most frequent deficits were found in attention (100%) and executive functions (85.3%).

Cognitive dysfunction correlated to psychotic features during the last episode (P=0.005), subsyndromal affective symptoms between episodes (P=0.13), high number of mood episodes (P=0.007) and hospitalisations (P=0.014).

Our study confirmed that cognitive dysfunction was frequent in older bipolar patients in Tunisia. Preventing mood episodes, screening for addictive and somatic co-morbidities, as well as cognitive rehabilitation, are suitable strategies for improving cognitive functioning among these patients.