Epidemiological and clinical variables related with the predominant polarity on bipolar disorder: A systematic review

Abstract

IntroductionType I and type II classification of bipolar disorder (BD) may not provide useful information to the clinician regarding epidemiological and clinical correlates.New classifications have recently been proposed, such as the Predominant Polarity (PP) classification, which is based on the tendency of the patient to relapse in the manic (Manic Predominant Polarity [MPP]) or the depressive (Depressive Predominant Polarity [DPP]) poles along the course of the disease.ObjectivesTo explore the epidemiological and clinical correlates of PP.MethodsWe performed a search of the PubMed and Web of Science databases up to June 1st 2016, using the keywords “bipolar disorder”, “polarity” and “predominant polarity”.ResultsThe initial search identified 1598 articles. Only 17 articles met inclusion criteria. Factors associated with MPP are manic onset, history of drug abuse and a better response to atypical antipsychotics and mood stabilizers. Meanwhile DPP is associated with depressive onset, more relapses, longer acute episodes, and a higher risk of suicide. Moreover, delay until diagnosis, mixed episodes and comorbid anxiety disorders are more prevalent in DPP patients, whose treatment often involves quetiapine and lamotrigine.LimitationsFew prospective studies. Variability of results.ConclusionsPP classification may be useful for the clinical management of BD. Further research in this field is needed. Future research should use standardized definitions and more comparable methods.Disclosure of interestThe authors have not supplied their declaration of competing interest.