title: Anhedonia and cognitive function in adults with MDD: results from the International Mood Disorders Collaborative Project.
abstract: BACKGROUND
  Cognitive dysfunction is common in major depressive disorder (MDD) and a critical determinant of health outcome. Anhedonia is a criterion item toward the diagnosis of a major depressive episode (MDE) and a well-characterized domain in MDD. We sought to determine the extent to which variability in self-reported cognitive function correlates with anhedonia.
  
  
  METHODS
  A post hoc analysis was conducted using data from (N=369) participants with a Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR)-defined diagnosis of MDD who were enrolled in the International Mood Disorders Collaborative Project (IMDCP) between January 2008 and July 2013. The IMDCP is a collaborative research platform at the Mood Disorders Psychopharmacology Unit, University of Toronto, Toronto, Canada, and the Cleveland Clinic, Cleveland, Ohio. Measures of cognitive function, anhedonia, and depression severity were analyzed using linear regression equations.
  
  
  RESULTS
  A total of 369 adults with DSM-IV-TR-defined MDD were included in this analysis. Self-rated cognitive impairment [ie, as measured by the Adult ADHD Self-Report Scale (ASRS)] was significantly correlated with a proxy measure of anhedonia (r=0.131, p=0.012). Moreover, total depression symptom severity, as measured by the total Montgomery-Åsberg Depression Rating Scale (MADRS) score, was also significantly correlated with self-rated measures of cognitive dysfunction (r=0.147, p=0.005). The association between anhedonia and self-rated cognitive dysfunction remained significant after adjusting for illness severity (r=0.162, p=0.007).
  
  
  CONCLUSIONS
  These preliminary results provide empirical data for the testable hypothesis that anhedonia and self-reported cognitive function in MDD are correlated yet dissociable domains. The foregoing observation supports the hypothesis of overlapping yet discrete neurobiological substrates for these domains.
authors.affiliation: 1Department of Psychiatry,University of Toronto,Toronto,Ontario,Canada.
authors.forename: Roger S
authors.initials: RS
authors.lastname: McIntyre
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Hanna O
authors.initials: HO
authors.lastname: Woldeyohannes
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Joanna K
authors.initials: JK
authors.lastname: Soczynska
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Nadia A
authors.initials: NA
authors.lastname: Maruschak
authors.affiliation: 5Department of Psychiatry,Psychiatric Center,Copenhagen,Denmark.
authors.forename: Ida K
authors.initials: IK
authors.lastname: Wium-Andersen
authors.affiliation: 5Department of Psychiatry,Psychiatric Center,Copenhagen,Denmark.
authors.forename: Maj
authors.initials: M
authors.lastname: Vinberg
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Danielle S
authors.initials: DS
authors.lastname: Cha
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Yena
authors.identifier: http://orcid.org/0000-0003-0629-9456
authors.initials: Y
authors.lastname: Lee
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Holly X
authors.initials: HX
authors.lastname: Xiao
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Laura Ashley
authors.initials: LA
authors.lastname: Gallaugher
authors.affiliation: 6Cleveland Clinic,Cleveland,Ohio,USA.
authors.forename: Roman M
authors.initials: RM
authors.lastname: Dale
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Mohammad T
authors.initials: MT
authors.lastname: Alsuwaidan
authors.affiliation: 3Mood Disorders Psychopharmacology Unit,University Health Network,Toronto,Ontario,Canada.
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: Mansur
authors.affiliation: 7Turn2Health Solutions,Willoughby,Ohio,USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Muzina
authors.affiliation: 8Translational Psychiatry Research Group and Department of Clinical Medicine, Faculty of Medicine,Federal University of Ceara,Fortaleza,Brazil.
authors.forename: Andre F
authors.initials: AF
authors.lastname: Carvalho
authors.affiliation: 9Department of Neuropsychiatry,University of South Carolina School of Medicine,Columbia,South Carolina,USA.
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Jerrell
authors.affiliation: 1Department of Psychiatry,University of Toronto,Toronto,Ontario,Canada.
authors.forename: Sidney H
authors.initials: SH
authors.lastname: Kennedy
mesh_terms: D000328:Adult; D059445:Anhedonia; D060825:Cognitive Dysfunction / Q000523:psychology*; D003430:Cross-Sectional Studies; D003863:Depression / Q000523:psychology; D003865:Major Depressive Disorder / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057566:Self Report; D012720:Severity of Illness Index
keywords: Anhedonia; cognitive impairment; major depressive disorder