title: The relationship between sleep-wake cycle and cognitive functioning in young people with affective disorders.
abstract: Although early-stage affective disorders are associated with both cognitive dysfunction and sleep-wake disruptions, relationships between these factors have not been specifically examined in young adults. Sleep and circadian rhythm disturbances in those with affective disorders are considerably heterogeneous, and may not relate to cognitive dysfunction in a simple linear fashion. This study aimed to characterise profiles of sleep and circadian disturbance in young people with affective disorders and examine associations between these profiles and cognitive performance. Actigraphy monitoring was completed in 152 young people (16-30 years; 66% female) with primary diagnoses of affective disorders, and 69 healthy controls (18-30 years; 57% female). Patients also underwent detailed neuropsychological assessment. Actigraphy data were processed to estimate both sleep and circadian parameters. Overall neuropsychological performance in patients was poor on tasks relating to mental flexibility and visual memory. Two hierarchical cluster analyses identified three distinct patient groups based on sleep variables and three based on circadian variables. Sleep clusters included a 'long sleep' cluster, a 'disrupted sleep' cluster, and a 'delayed and disrupted sleep' cluster. Circadian clusters included a 'strong circadian' cluster, a 'weak circadian' cluster, and a 'delayed circadian' cluster. Medication use differed between clusters. The 'long sleep' cluster displayed significantly worse visual memory performance compared to the 'disrupted sleep' cluster. No other cognitive functions differed between clusters. These results highlight the heterogeneity of sleep and circadian profiles in young people with affective disorders, and provide preliminary evidence in support of a relationship between sleep and visual memory, which may be mediated by use of antipsychotic medication. These findings have implications for the personalisation of treatments and improvement of functioning in young adults early in the course of affective illness.
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Joanne S
authors.initials: JS
authors.lastname: Carpenter
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Rébecca
authors.initials: R
authors.lastname: Robillard
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Rico S C
authors.initials: RS
authors.lastname: Lee
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hermens
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Naismith
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Django
authors.initials: D
authors.lastname: White
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Bradley
authors.initials: B
authors.lastname: Whitwell
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Scott
authors.affiliation: Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Hickie
mesh_terms: D056044:Actigraphy; D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D002940:Circadian Rhythm; D016000:Cluster Analysis; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D019964:Mood Disorders / Q000188:drug therapy / Q000503:physiopathology*; D009483:Neuropsychological Tests; D012890:Sleep; D020178:Sleep Disorders, Circadian Rhythm / Q000188:drug therapy / Q000503:physiopathology*; D014851:Wakefulness
chemical_list: D014150:Antipsychotic Agents