title: Executive dysfunction and cognitive subgroups in a large sample of euthymic patients with bipolar disorder.
abstract: Bipolar disorder (BP), at the group level, is associated with significant but modest cognitive deficits, including executive dysfunction. Among executive functions, response inhibition deficits have been suggested to be particularly relevant to BP. However, BP is associated with significant heterogeneity in neurocognitive performance and level of functioning. Very few studies have investigated neurocognitive subgroups in BP with data-driven methods rather than arbitrarily defined criteria. Other than having relatively small sample sizes, previous studies have not taken into consideration the neurocognitive variability in healthy subjects. Five-hundred-fifty-six euthymic patients with BP and 416 healthy controls were assessed using a battery of cognitive tests and clinical measures. Neurocognitive subgroups were investigated using latent class analysis, based on executive functions. Four neurocognitive subgroups, including a good performance cluster, two moderately low-performance groups, which differ in response inhibition and reasoning abilities, and a severe impairment cluster were found. In comparison to healthy controls, BP patients were overrepresented in severe impairment cluster (27% vs 5.3%) and underrepresented in good performance cluster. BP patients with lower educational attainment and older age were significantly more likely to be members of cognitively impaired subgroups. Antipsychotic use was less common in good performance cluster. These results suggest that there is a considerable overlap of cognitive functions between BP and healthy controls. Neurocognitive differences between BP and healthy controls are driven by a subgroup of patients who have severe and global, rather than selective, cognitive deficits.
authors.affiliation: The Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, VIC, Australia. Electronic address: ibora@unimelb.edu.au.
authors.forename: Emre
authors.initials: E
authors.lastname: Bora
authors.affiliation: Department of Psychology, Faculty of Arts, Dokuz Eylul University, Izmir, Turkey.
authors.forename: Ceren
authors.initials: C
authors.lastname: Hıdıroğlu
authors.affiliation: Dokuz Eylül University, Faculty of Medicine, Department of Psychiatry, Izmir, Turkey; Dokuz Eylul University, Health Sciences Institute, Department of Neurosciences, Izmir, Turkey.
authors.forename: Ayşegül
authors.initials: A
authors.lastname: Özerdem
authors.affiliation: Ondokuz Mayıs University, Faculty of Medicine, Department of Psychiatry, Samsun, Turkey.
authors.forename: Ömer Faruk
authors.initials: ÖF
authors.lastname: Kaçar
authors.affiliation: Ondokuz Mayıs University, Faculty of Medicine, Department of Psychiatry, Samsun, Turkey.
authors.forename: Gökhan
authors.initials: G
authors.lastname: Sarısoy
authors.affiliation: Karadeniz Technical University, Faculty of Medicine, Department of Psychiatry, Trabzon, Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Civil Arslan
authors.affiliation: Celal Bayar University, Faculty of Medicine, Department of Psychiatry, Manisa, Turkey.
authors.forename: Ömer
authors.initials: Ö
authors.lastname: Aydemir
authors.affiliation: Izmir University, Faculty of Medicine, Department of Child and adolescent psychiatry, Izmir, Turkey.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Cubukcuoglu Tas
authors.affiliation: Ege University, Faculty of Medicine, Department of Psychiatry, Izmir, Turkey.
authors.forename: Simavi
authors.initials: S
authors.lastname: Vahip
authors.affiliation: Bülent Ecevit University, Faculty of Medicine, Department of Psychiatry, Zonguldak, Turkey.
authors.forename: Adnan
authors.initials: A
authors.lastname: Atalay
authors.affiliation: Bülent Ecevit University, Faculty of Medicine, Department of Psychiatry, Zonguldak, Turkey.
authors.forename: Nuray
authors.initials: N
authors.lastname: Atasoy
authors.affiliation: Pamukkale University, Faculty of Medicine, Department of Psychiatry, Denizli, Turkey.
authors.forename: Figen
authors.initials: F
authors.lastname: Ateşci
authors.affiliation: Pamukkale University, Faculty of Medicine, Department of Psychiatry, Denizli, Turkey.
authors.forename: Selim
authors.initials: S
authors.lastname: Tümkaya
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000145:classification / Q000188:drug therapy / Q000503:physiopathology* / Q000523:psychology; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004522:Educational Status; D056344:Executive Function; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D010044:Outpatient Clinics, Hospital; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index; D013223:Statistics as Topic; D014421:Turkey / Q000453:epidemiology
chemical_list: D014150:Antipsychotic Agents
keywords: Bipolar disorder; Cognitive heterogeneity; Latent class analysis; Neurocognition