Age of onset of illness may be useful in explaining the heterogeneity among older bipolar patients.

To examine the relationship of age of onset with clinical, demographic and behavioral variables, in older patients with bipolar disorder.

This was a cross-sectional, descriptive and analytical study, including 24 patients suffering from bipolar disorders, aged 65 years or more and followed-up in outpatient psychiatry unit at Hedi Chaker university hospital in Sfax in Tunisia. We used a standardized questionnaire including socio-demographic, behavioral and clinical data. Age of onset was split at age 40 years into early-onset (< 40 years; n = 12) and late-onset (≥ 40 years; n = 12) groups.

The mean age for the entire sample was 68.95 years. The mean age of onset was 39.95 years. The majority (60%) of patients were diagnosed with bipolar I. Few meaningful differences emerged between early-onset and late-onset groups, except that tobacco use was significantly higher in the late-onset group (66.6% vs. 16.6%; P = 0.027). No significant differences between the early-onset and late-onset groups were seen on demographic variables, family history and number of medical diagnoses or presence of psychotic features.

Our study found few meaningful behavioral differences between early versus late age at onset in older adults with bipolar disorder.

The authors have not supplied their declaration of competing interest.