title: The prevalence and predictors of comorbid bipolar disorder and obsessive-compulsive disorder: A systematic review and meta-analysis.
abstract: BACKGROUND
  Although some authors have recently investigated the co-occurrence of anxiety and bipolar disorders, the topic remains insufficiently studied. Defining the prevalence and predictors of BD-OCD comorbidity has important nosological, clinical and therapeutic implications.
  
  
  METHODS
  A systematic review and meta-analysis was conducted on the prevalence and predictors of comorbid BD-OCD. Relevant papers published through March 30th, 2015 were identified searching the electronic databases MEDLINE, Embase, PsycINFO and the Cochrane Library.
  
  
  RESULTS
  46 articles met inclusion criteria. The pooled prevalence of OCD in BD was 17.0% (95% CI 12.7-22.4%), which was comparable to the results reported by the pooled prevalence of BD in OCD (18.35%, 95% CI 13.2-24.8%). With regard to OCD-BD predictors, a higher mean age predicted a lower prevalence of OCD in BD patients. Sub group meta-analyses reported higher OCD prevalence rates in BD children and adolescents (24.2%, compared to 13.5% in adults), in BD-I patients (24.6%, compared to 13.6% in mixed BD patients), and among population-based studies (22.2%, compared to 13.2% in hospital-based studies).
  
  
  CONCLUSIONS
  Most studies use retrospective assessment scales with low sensitivity in discriminating true ego-dystonic obsessions from depressive ruminations that may bias results towards an overestimation of obsessive symptom prevalence.
  
  
  CONCLUSIONS
  This first systematic review and meta-analysis of the prevalence and predictors of comorbid BD-OCD confirms that BD-OCD comorbidity is a common condition in psychiatry with children and adolescents and BD-I patients as the most affected subgroups.
authors.affiliation: Department of Neuroscience, Section of Psychiatry, University of Parma, Parma, Italy; Mood Disorders Program, Tufts Medical Center, Boston, MA, USA. Electronic address: andrea.amerio@studenti.unipr.it.
authors.forename: A
authors.initials: A
authors.lastname: Amerio
authors.affiliation: School of Health and Social Care, University of Greenwich, London, UK. Electronic address: brendon.stubbs@kcl.ac.uk.
authors.forename: B
authors.initials: B
authors.lastname: Stubbs
authors.affiliation: School of Medicine-Public Health Unit, University of Parma, Parma, Italy; Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, USA. Electronic address: anna.odone@mail.harvard.edu.
authors.forename: A
authors.initials: A
authors.lastname: Odone
authors.affiliation: Department of Mental Health, Local Health Service, Parma, Italy. Electronic address: mtonna@ausl.pr.it.
authors.forename: M
authors.initials: M
authors.lastname: Tonna
authors.affiliation: Department of Neuroscience, Section of Psychiatry, University of Parma, Parma, Italy; Department of Mental Health, Local Health Service, Parma, Italy. Electronic address: carlo.marchesi@unipr.it.
authors.forename: C
authors.initials: C
authors.lastname: Marchesi
authors.affiliation: Mood Disorders Program, Tufts Medical Center, Boston, MA, USA; Tufts University Medical School, Department of Psychiatry and Pharmacology, Boston, MA, USA. Electronic address: nghaemi@tuftsmedicalcenter.org.
authors.forename: S N
authors.initials: SN
authors.lastname: Ghaemi
mesh_terms: D000367:Age Factors; D001714:Bipolar Disorder / Q000453:epidemiology*; D015897:Comorbidity; D006801:Humans; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology*; D015995:Prevalence
keywords: Bipolar disorder; Obsessive–compulsive disorder; predictors; prevalence