title: Parental and comorbid epilepsy in persons with bipolar disorder.
abstract: BACKGROUND
  Population-based studies have demonstrated an overrepresentation of bipolar disorder (BPD) in individuals with epilepsy. However, few studies have examined the reverse association, i.e. comorbid epilepsy in individuals selected based on BPD diagnosis. No previous population-based study having examined the co-occurrence of BPD and epilepsy has adjusted for parental psychopathology. Such an adjustment is motivated by population-based studies reporting an overrepresentation of various types of parental psychiatric disorders in both BPD and epilepsy. Furthermore, an association between epilepsy in first-degree relatives and BPD has previously only been examined and demonstrated in a small clinical sample. The objective of this study is to examine the associations between parental and comorbid epilepsy and BPD, adjusting for parental psychopathology.
  
  
  METHODS
  This nested case-control study identified 1861 cases with BPD, age up to 25 years, 3643 matched controls, and their parents from Finnish national registers. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) and two-sided significance limits of p<0.05.
  
  
  RESULTS
  BPD was associated with comorbid epilepsy (adjusted OR 2.53, 95% CI: 1.73-3.70) but not with parental epilepsy. Epilepsy was found in 3.33% of cases versus 1.29% of controls, 2.69% of cases' parents versus 2.53% of controls' parents.
  
  
  CONCLUSIONS
  The diagnoses were register-based, not based on standardized procedures with direct ascertainment.
  
  
  CONCLUSIONS
  An association between BPD and comorbid epilepsy persists even after adjusting for parental psychopathology. Lack of familial clustering of BPD and epilepsy would suggest that the elevated co-occurrence of these disorders is influenced by non-genetic factors.
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland. Electronic address: dansuc@utu.fi.
authors.forename: Dan
authors.initials: D
authors.lastname: Sucksdorff
authors.affiliation: Department of Psychiatry, Columbia University Medical Center, New York State Psychiatric Institute, New York, NY, USA; Department of Epidemiology, Columbia University Mailman School of Public Health, New York, NY, USA.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Brown
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Roshan
authors.initials: R
authors.lastname: Chudal
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Elina
authors.initials: E
authors.lastname: Jokiranta-Olkoniemi
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Leivonen
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Auli
authors.initials: A
authors.lastname: Suominen
authors.affiliation: Department of Psychiatry, University of Turku, Turku, Finland.
authors.forename: Markus
authors.initials: M
authors.lastname: Heinimaa
authors.affiliation: Research Centre for Child Psychiatry, University of Turku, Turku, Finland; Department of Child Psychiatry, University of Turku, Turku, Finland.
authors.forename: Andre
authors.initials: A
authors.lastname: Sourander
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000453:epidemiology / Q000523:psychology*; D016022:Case-Control Studies; D015984:Causality; D016241:Child of Impaired Parents / Q000523:psychology* / Q000706:statistics & numerical data; D015897:Comorbidity; D004827:Epilepsy / Q000453:epidemiology / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010290:Parents / Q000523:psychology*; D012307:Risk Factors; D055815:Young Adult
keywords: Bipolar disorder; Epidemiology; Epilepsy; Parental psychopathology; Population-based study; Register