Rapid-cycling affective disorder in the elderly: clinical subtype or specific course of manic-depressive illness?

Rapid cycling is a relatively unusual presentation of bipolar affective disorder in the elderly. Four cases or rapid-cycling affective disorder (RCAD) in elderly women (aged 78-86 yr) are presented. Two patients began their bipolar illness in adulthood (aged 30 and 49 yr), and rapid cycles appeared secondarily in their elderly years (82 and 76 yr). The other two began their illness immediately with rapid cycles respectively at the age of 62 and 66. Added to the nine cases of RCAD in the elderly previously reported in the literature, a meta-analysis conducted on this small sample suggests that immediate entry in rapid cycles seems more likely to be associated with a late occurrence of bipolar illness (after 60 years of age)(P = .0035, Fisher's Exact Test, two-tailed), and that very short cycles (< 2 weeks each) are more likely to be associated with female gender (P = .0047, Fisher's Exact Test, two-tailed). Despite the small size of the sample, these results give some arguments to the hypothesis that RCAD is not a homogeneous syndrome but could be considered as a pattern of evolution, as well as clinical subtype, of the bipolar illness.