title: Prevalence, impact and treatment of generalised anxiety disorder in bipolar disorder: a systematic review and meta-analysis.
abstract: Recent data suggest that anxiety disorders are as often comorbid with bipolar disorder (BD) as with unipolar depression; however, less attention has been paid to comorbidity of anxiety disorders with BD. Generalised anxiety disorder (GAD) is one of the most prevalent anxiety disorders that is highly comorbid with other mental disorders. We carried out a systematic review and meta-analysis to assess the degree of comorbidity between GAD and BD.
  
  
  
  We searched for all studies, which included primary data concerning the existence of GAD in patients with BD. The literature search strategy, selection of publications and the reporting of results have been conducted with PRISMA guidelines. The meta-analysis calculated prevalence estimates using the variance-stabilising Freeman-Tukey double arcsine transformation. We applied the inverse variance method using both fixed-effects and random-effects models to estimate summary effects for all combined studies. Heterogeneity was assessed and measured with Cochran's Q and I(2) statistics, respectively.
  
  
  
  The current meta-analysis analysed data from 28 independent studies and a total of 2975 patients from point prevalence studies and 4919 patients from lifetime studies. The overall random-effects point prevalence of GAD in patients with BD was 12.2% (95% CI 10.9% to 13.5%) and the overall random-effects lifetime estimate was 15.1% (95% CI 9.7% to 21.5%). Both estimates reported significant heterogeneity (94.0% and 94.7%, respectively).
  
  
  
  Published studies report prevalence rates with high heterogeneity and consistently higher than those typically reported in the general population. It is believed that comorbid GAD might be associated with a more severe BD course and increased suicidality, and it is unknown how best to treat such conditions. The current meta-analysis confirms that GAD is highly prevalent in BD and the rate is higher in comparison to those in the general population.
authors.affiliation: Genneruxi Medical Center, Cagliari, Italy Center for Consultation-Liaison Psychiatry and Psychosomatics, University Hospital of Cagliari, Cagliari, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Preti
authors.affiliation: Department of Psychiatry and Narcology, Riga Stradins University, Riga, Latvia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Vrublevska
authors.affiliation: Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Areti Angeliki
authors.initials: AA
authors.lastname: Veroniki
authors.affiliation: Department of Allied Health Sciences, University of Connecticut, Storrs, Connecticut, USA.
authors.forename: Tania B
authors.initials: TB
authors.lastname: Huedo-Medina
authors.affiliation: 3rd Department of Psychiatry, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Konstantinos N
authors.initials: KN
authors.lastname: Fountoulakis
mesh_terms: D001008:Anxiety Disorders / Q000150:complications / Q000453:epidemiology* / Q000523:psychology / Q000628:therapy*; D001714:Bipolar Disorder / Q000150:complications / Q000453:epidemiology*; D015897:Comorbidity; D006801:Humans; D015995:Prevalence