title: Formal thought disorder in schizophrenia and bipolar disorder: A systematic review and meta-analysis.
abstract: Historically, formal thought disorder has been considered as one of the distinctive symptoms of schizophrenia. However, research in last few decades suggested that there is a considerable clinical and neurobiological overlap between schizophrenia and bipolar disorder (BP). We conducted a meta-analysis of studies comparing positive (PTD) and negative formal thought disorder (NTD) in schizophrenia and BP. We included 19 studies comparing 715 schizophrenia and 474 BP patients. In the acute inpatient samples, there was no significant difference in the severity of PTD (d=-0.07, CI=-0.22-0.09) between schizophrenia and BP. In stable patients, schizophrenia was associated with increased PTD compared to BP (d=1.02, CI=0.35-1.70). NTD was significantly more severe (d=0.80, CI=0.52-0.1.08) in schizophrenia compared to BP. Our findings suggest that PTD is a shared feature of both schizophrenia and BP but persistent PTD or NTD can distinguish subgroups of schizophrenia from BP and schizophrenia patients with better clinical outcomes.
authors.affiliation: Department of Neurosciences, Dokuz Eylül University, Izmir 35340, Turkey. Electronic address: bernayalincetin@hotmail.com.
authors.forename: Berna
authors.initials: B
authors.lastname: Yalincetin
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Carlton South, Victoria 3053, Australia; Department of Psychiatry, Dokuz Eylül University Medical School, Izmir 35340, Turkey.
authors.forename: Emre
authors.initials: E
authors.lastname: Bora
authors.affiliation: Department of Psychiatry, Dokuz Eylül University Medical School, Izmir 35340, Turkey.
authors.forename: Tolga
authors.initials: T
authors.lastname: Binbay
authors.affiliation: Department of Psychiatry, Dokuz Eylül University Medical School, Izmir 35340, Turkey.
authors.forename: Halis
authors.initials: H
authors.lastname: Ulas
authors.affiliation: Department of Neurosciences, Dokuz Eylül University, Izmir 35340, Turkey; Department of Psychiatry, Dokuz Eylül University Medical School, Izmir 35340, Turkey.
authors.forename: Berna Binnur
authors.initials: BB
authors.lastname: Akdede
authors.affiliation: Department of Neurosciences, Dokuz Eylül University, Izmir 35340, Turkey; Department of Psychiatry, Dokuz Eylül University Medical School, Izmir 35340, Turkey.
authors.forename: Koksal
authors.initials: K
authors.lastname: Alptekin
mesh_terms: D001714:Bipolar Disorder / Q000503:physiopathology*; D006801:Humans; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013850:Thinking / Q000502:physiology*
keywords: Bipolar disorder; Formal thought disorder; Schizophrenia