Bipolar Disorder: Similarities and Differences Between Patients With Illness Onset Before and After 65 Years of Age

Abstract

Background: Recent reports have suggested that bipolar disorder beginning in late life is strongly associated with organic brain disease whereas early-onset cases are more likely to be associated with a family history of mood disorder. It is not yet clear whether late-onset bipolar disorder is therefore a “phenocopy” of the classic early-onset disorder, sharing symptoms but having a different etiology, or whether people with early- and late-onset bipolar disorder have a common underlying vulnerability that interacts with age-specific triggering factors. Aim: The present study examines the administrative records of patients treated for bipolar disorder, to establish whether differences between early- and late-onset cases might be consistent with their having distinct etiological processes. Methods: We used a file containing administrative data for all patients with a diagnosis of bipolar disorder who were in contact with the health services of Western Australia between 1980 and 1998. For each contact with psychiatric services, the file provided the patient's age, gender, marital status, educational achievement, employment, ethnic origin, postcode of residence, primary and secondary diagnoses, and the duration of the (administrative) episode. Subjects were designated “late-onset” when their first contact with psychiatric services occurred at or after 65 years of age. Results: Between 1980 and 1998 there were 33,004 service contacts involving 6,182 individuals whose primary or secondary clinical diagnosis was bipolar disorder. This indicates that the prevalence of bipolar disorder in Western Australia is approximately 0.4%. Most patients had an onset of illness between 15 and 45 years of age, but 492 patients (8%) were aged 65 years or over at the time of first contact with mental health services. We observed that the relative frequency of late-onset bipolar disorder increased between 1980 and 1998 (1% to 11%). There was an excess of women in our cohort (3:2), but no difference in the age of onset between males and females. Early onset was associated with a subsequently lower socioeconomic status, aboriginal ethnicity, and a higher frequency of mixed affective episodes, other mood disorders, schizophrenia, and schizoaffective disorder. Patients with late-onset bipolar disorder were more likely to have a diagnosis of organic mental disorder recorded (2.8% vs. 1.2%). There was no evidence of a bimodal pattern of age-specific incidence. Conclusion: The observed differences between early- and late-onset bipolar disorders are small and most likely attributable to differences in the duration of illness. Only a small proportion of patients with bipolar disorder were ever diagnosed with an organic mental disorder, which suggests that the reported association between late onset of illness and organic factors may be of limited clinical relevance.

Transtorno bipolar de início tardio: uma variedade orgânica do transtorno de humor?

“…We have recently evaluated the age at onset for the entire population of patients with BD in contact with the Western Australian health services between 1980 and 1998. 4 We found no evidence for a bimodal distribution of the age at onset of illness in this population, as had been previously suggested by Broadhead and Jacoby 5 ( Figure). Of course, this finding could be potentially explained by the fact that these patients might have been correctly diagnosed as suffering from an organic mental disorder rather than BD.…”

“…The onset of symptoms is usually placed between the ages of 18 and 22 years, [1][2] although a substantial proportion of patients develop the condition later in life. 3 Almeida and Fenner, 4 for example, found that 492/6182 patients with BD had illness onset at or after the age of 65 years (8% of the total sample), confirming that mania may arise for the first-ever time amongst older adults. Broadhead and Jacoby 5 observed that the distribution of age at onset amongst 35 hospitalised older adults with BD living in London was bimodal, with an early and late onset peak, which reinforced the speculation that BD with late onset may be more strongly associated with 'organic factors' than in early onset cases.…”

“…4 Symptoms typically arise amongst people in their 20s, but the onset of the illness is certainly not limited to young adulthood. Whilst an array of medical conditions and drugs are thought to increase the risk of mania, their presence cannot adequately explain the relatively large proportion of cases of BD with onset in later life.…”

Dépression du sujet âgé : données épidémiologiques, aspects cliniques et approches thérapeutiques spécifiques

“…Concernant la dépression avec caractéristiques psychotiques, en population générale là encore, c'est dans la tranche d'âge des 65 ans et plus que le taux de prévalence est le plus élevé [13]. Pour le trouble bipolaire, même si la moitié des cas sont diagnostiqués avant l'âge de 35 ans, 15 à 20 % le sont après 55 ans [14].…”

Use of Lithium in the Treatment of Bipolar Disorder in Late-Life

“…This burden is particularly high among older adults, as older patients with bipolar disorder have a higher mortality rate and use more mental health services than younger patients [3,4]. As the general population continues to age and the awareness of this disorder among older adults continues to increase [5], the costs of late-life bipolar disorder are likely to grow in the future.…”