An increased proportional representation of bipolar disorder in younger depressed patients: analysis of two clinical databases.
OBJECTIVE
To pursue the suggested increased incidence of bipolar disorder by examining for a cohort effect in the proportional representation of Bipolar Disorder in two independent clinical samples of depressed patients.


METHODS
Assessment of polarity status was undertaken with some consistency over defined collection periods in two independent samples.


RESULTS
The lifetime proportional rates of bipolar disorder declined with age from some 60% to 30% in both samples.


CONCLUSIONS
The strikingly similar age-related pattern in both samples and the linear trajectory support a cohort effect where the incidence of bipolar disorder may be increasing disproportionately in younger individuals.
Parker
Gordon
G
School of Psychiatry, University of New South Wales; Black Dog Institute, Sydney, Australia. g.parker@unsw.edu.au
Brotchie
Heather
H
Fletcher
Kathryn
K
D000328:Adult; D017677:Age Distribution; D001714:Bipolar Disorder / Q000453:epidemiology*; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged