Predominant polarity as a course specifier for bipolar disorder: a systematic review.
BACKGROUND
Predominant polarity (PP) is a proposed course specifier for bipolar disorder, which was not incorporated in the DSM-5 as a descriptor for the nosology of bipolar disorder (BD). Here we perform a systematic review of original studies about PP.


METHODS
A computerized search of MEDLINE/Pubmed, EMBASE and Web of Science databases from inception to October 6th, 2013 was performed with keywords, including 'bipolar disorder', 'polarity' and 'predominant polarity'.


RESULTS
A total of 19 studies met inclusion criteria. A unifying definition and conceptualization for PP is lacking. A PP is found in approximately half of BD patients. Most studies that included type I BD patients found the manic PP to be more prevalent, while studies that included type II BD participants found a higher prevalence of depressive PP. The depressive PP has been consistently associated with a depressive onset of illness, a delayed diagnosis of BD, type II BD and higher rates of suicidal acts. The manic PP is associated with a younger onset of illness, a first episode manic/psychotic and a higher rate of substance abuse. Evidence suggests that PP may influence responses to acute treatment for bipolar depression. Furthermore, evidences indicate that PP should be considered for the selection of maintenance treatments for BD.


CONCLUSIONS
There are few prospective studies on PP. There were disparate definitions for PP across studies.


CONCLUSIONS
The concept of PP provides relevant information for clinicians. Future studies should investigate the genetic and biological underpinnings of PP.
Department of Clinical Medicine and Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil. Electronic address: andrefc7@terra.com.br.
André F
AF
Carvalho
Department of Psychiatry and Mood Disorders Psychopharmacology Unit, University of Toronto, Toronto, ON, Canada.
Roger S
RS
McIntyre
3rd Department of Psychiatry, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Dimos
D
Dimelis
Department of Clinical and Theoretical Mental Health, Kutvolgyi Clinical Center, Semmelweis University, Budapest, Hungary; Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary; Neuropsychopharmacology and Neurochemistry Research Group, National Academy of Sciences and Semmelweis University, Budapest, Hungary; National Institute of Psychiatry and Addictions, Laboratory for Suicide Research and Prevention, Budapest, Hungary.
Xenia
X
Gonda
IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, VIC, Australia; Department of Psychiatry, The Florey Institute of Neuroscience and Mental Health, and Orygen Youth Health Research Centre, University of Melbourne, Parkville, VIC, Australia.
Michael
M
Berk
Department of Clinical Medicine and Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil.
Paulo R
PR
Nunes-Neto
Department of Psychiatry and Mood Disorders Psychopharmacology Unit, University of Toronto, Toronto, ON, Canada.
Danielle S
DS
Cha
Department of Psychiatry, University of Ioaninna, Ioaninna, Greece.
Thomas N
TN
Hyphantis
Department of Psychiatry, Psychotherapy and Psychosomatics, Zurich University Hospital, Zurich, Switzerland.
Jules
J
Angst
3rd Department of Psychiatry, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Konstantinos N
KN
Fountoulakis
D017668:Age of Onset; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D006801:Humans; D015995:Prevalence
Bipolar disorder; Depression; Diagnosis; Mania; Predominant polarity; Treatment