title: Differences and overlap in self-reported symptoms of bipolar disorder and borderline personality disorder.
abstract: BACKGROUND
  Differential diagnosis between bipolar disorder (BD) and borderline personality disorder (BPD) is often challenging due to some overlap in symptoms and comorbidity of disorders. We investigated correlations in self-reported symptoms of BD and BPD in screening questionnaires at the levels of both total scores and individual items and explored overlapping dimensions.
  
  
  METHODS
  The McLean Screening Instrument (MSI) for BPD and the Mood Disorder Questionnaire (MDQ) for BD were filled in by patients with unipolar and bipolar mood disorders (n=313) from specialized psychiatric care within a pilot study of the Helsinki University Psychiatric Consortium. Pearson's correlation coefficients between total scores and individual items of the MSI and the MDQ were estimated. Relationships between MDQ and MSI were evaluated by exploratory factor analysis (EFA).
  
  
  RESULTS
  The correlation between total scores of the MDQ and MSI was moderate (r=0.431, P<0.001). Significant correlations were found between the MSI items of "impulsivity" and "mood instability" and all MDQ items (P<0.01). In the EFA, the MSI "impulsivity" and "mood instability" items had significant cross-loadings (0.348 and 0.298, respectively) with the MDQ factor. The MDQ items of "irritability", "flight of thoughts" and "distractibility" (0.280, 0.210 and 0.386, respectively) cross-loaded on the MSI factor.
  
  
  CONCLUSIONS
  The MDQ and MSI items of "affective instability", "impulsivity", "irritability", "flight of thoughts" and "distractibility" appear to overlap in content. The other scale items are more disorder-specific, and thus, may help to distinguish BD and BPD.
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Baryshnikov
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland; Department of Social Services and Health Care, Helsinki, Finland; Department of Psychiatry, Helsinki University Central Hospital, PO Box 590, 00029 HUS, Helsinki, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Aaltonen
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Koivisto
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Näätänen
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland.
authors.forename: B
authors.initials: B
authors.lastname: Karpov
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland; Department of Psychiatry, Helsinki University Central Hospital, PO Box 590, 00029 HUS, Helsinki, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Melartin
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland; Department of Social Services and Health Care, Helsinki, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Heikkinen
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland; Operations and Technology Department, IE Business School - IE University, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Ketokivi
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland.
authors.forename: G
authors.initials: G
authors.lastname: Joffe
authors.affiliation: Department of Psychiatry, University of Helsinki and Helsinki University Hospital, PO Box 22, Välskärinkatu 12 A, 00014 Helsinki, Finland. Electronic address: erkki.isometsa@hus.fi.
authors.forename: E
authors.initials: E
authors.lastname: Isometsä
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000523:psychology*; D001883:Borderline Personality Disorder / Q000175:diagnosis* / Q000523:psychology*; D015897:Comorbidity; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007175:Impulsive Behavior; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011594:Psychometrics; D015203:Reproducibility of Results; D057566:Self Report; D011795:Surveys and Questionnaires
keywords: Bipolar disorder; Borderline personality disorder; McLean Screening Instrument; Mood Disorder Questionnaire