title: Sex differences in the risk of rapid cycling and other indicators of adverse illness course in patients with bipolar I and II disorder.
abstract: OBJECTIVE
  To examine the independent effects of sex on the risk of rapid cycling and other indicators of adverse illness course in patients with bipolar I disorder (BP-I) or bipolar II disorder (BP-II).
  
  
  METHODS
  We analyzed data from the first 1,225 patients enrolled in the Mayo Clinic Individualized Medicine Biobank for Bipolar Disorder. Demographic and clinical variables were ascertained using standardized questionnaires; height and weight were assessed to determine body mass index (BMI). Rates of rapid cycling, cycle acceleration, and increased severity of mood episodes over time were compared between women and men overall and within subgroups defined by bipolar disorder subtype (BP-I or BP-II). Multiple logistic regression analysis was used to assess the independent effect of sex on the risk of these indicators of adverse illness course.
  
  
  RESULTS
  Women had significantly higher rates of rapid cycling than men. Overall rates of rapid cycling were higher in patients with BP-II than BP-I; and sex differences in the rate of rapid cycling were more pronounced in patients with BP-II than BP-I, although the power to detect statistically significant differences was reduced due to the lower sample size of subjects with BP-II. Female sex was a significant predictor of rapid cycling, cycle acceleration, and increased severity of mood episodes over time after adjusting for age, bipolar disorder subtype, BMI, having any comorbid psychiatric disorder, and current antidepressant use.
  
  
  CONCLUSIONS
  Female sex was associated with significantly higher risk of rapid cycling, cycle acceleration, and increased severity of mood episodes over time in a sample of 1,225 patients with bipolar disorders.
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA.|Department of Psychiatry, Ataturk Education and Research Hospital, Izmir, Turkey.
authors.forename: Almila
authors.initials: A
authors.lastname: Erol
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Stacey J
authors.initials: SJ
authors.lastname: Winham
authors.affiliation: Lindner Center of HOPE, Mason, OH, USA.|University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Susan L
authors.initials: SL
authors.lastname: McElroy
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Frye
authors.affiliation: Departamento de Psiquiatría, Facultad de Medicina, Universidad de los Andes, Santiago, Chile.
authors.forename: Miguel L
authors.identifier: http://orcid.org/0000-0001-5578-4605
authors.initials: ML
authors.lastname: Prieto
authors.affiliation: Department of Psychiatry, Universidad Autonoma de Nuevo Leon, Monterrey, Mexico.
authors.forename: Alfredo B
authors.initials: AB
authors.lastname: Cuellar-Barboza
authors.affiliation: Department of Psychiatry, Universite Desarrollo and Clinica Allemana, Santiago, Chile.
authors.forename: Manuel
authors.initials: M
authors.lastname: Fuentes
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Geske
authors.affiliation: Lindner Center of HOPE, Mason, OH, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Mori
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA.|Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Biernacka
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA.
authors.forename: William V
authors.initials: WV
authors.lastname: Bobo
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D000928:Antidepressive Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology; D015992:Body Mass Index; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062072:Patient Acuity; D011569:Psychiatric Status Rating Scales; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires
chemical_list: D000928:Antidepressive Agents
keywords: bipolar disorder; cycle acceleration; gender; increased episode severity; rapid cycling; sex