An increased proportional representation of bipolar disorder in younger depressed patients: Analysis of two clinical databases

ObjectiveTo 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.MethodAssessment of polarity status was undertaken with some consistency over defined collection periods in two independent samples.ResultsThe lifetime proportional rates of bipolar disorder declined with age from some 60% to 30% in both samples.ConclusionsThe 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.