Late-onset bipolar-illness (LOBI) diagnosis comprises those patients whose first mania episode occurs aged 60 or older. Traditionally, it has been considered as a secondary disorder, accompanying other conditions such as dementia. While this is true for some cases, LOBI is a wider concept, which has its own features and also includes other entities.

To describe the main features of LOBI.

Critical review of the literature and description of the case of a 72-year-old woman diagnosed with LOBI.

While only 6–8% of all new cases of bipolar disorder (BD) occur in people older than 60, recent research suggests an increase of first episodes in this age group. LOBI is less associated with family history compared to early onset BD and seems to occur more frequently in women.

LOBI presents with better premorbid functioning and atypical psychopathology as compared to early onset. Also, there is a higher prevalence of mixed episodes and a higher frequency of episodes per year, with a great risk of suicide. LOBI patients have more cognitive impairment and higher rates of comorbid psychiatric disorders.

These patients show some specific neuroimaging signs, including subcortical hyperintensities.

Quetiapine and valproate have proved useful, but the pharmacokinetic and pharmacodynamic characteristics of older patients must be taken into account.

The reported case identifies similarities between LOBI and classical BD. However, both this case and the literature review reveal that LOBI has specific features that differentiate it from classical BD. Further research is needed to characterise the condition and improve its management.

The authors have not supplied their declaration of competing interest.