title: Distinct Subtypes of Apathy Revealed by the Apathy Motivation Index.
abstract: Apathy is a debilitating but poorly understood disorder characterized by a reduction in motivation. As well as being associated with several brain disorders, apathy is also prevalent in varying degrees in healthy people. Whilst many tools have been developed to assess levels of apathy in clinical disorders, surprisingly there are no measures of apathy suitable for healthy people. Moreover, although apathy is commonly comorbid with symptoms of depression, anhedonia and fatigue, how and why these symptoms are associated is unclear. Here we developed the Apathy-Motivation Index (AMI), a brief self-report index of apathy and motivation. Using exploratory factor analysis (in a sample of 505 people), and then confirmatory analysis (in a different set of 479 individuals), we identified subtypes of apathy in behavioural, social and emotional domains. Latent profile analyses showed four different profiles of apathy that were associated with varying levels of depression, anhedonia and fatigue. The AMI is a novel and reliable measure of individual differences in apathy and might provide a useful means of probing different mechanisms underlying sub-clinical lack of motivation in otherwise healthy individuals. Moreover, associations between apathy and comorbid states may be reflective of problems in different emotional, social and behavioural domains.
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
authors.forename: Yuen-Siang
authors.identifier: http://orcid.org/0000-0002-9353-6837
authors.initials: YS
authors.lastname: Ang
authors.affiliation: Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.|Division of Psychology and Language Sciences, University College London, London, United Kingdom.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lockwood
authors.affiliation: Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
authors.forename: Matthew A J
authors.initials: MA
authors.lastname: Apps
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.|Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
authors.forename: Kinan
authors.initials: K
authors.lastname: Muhammed
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.|Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
authors.forename: Masud
authors.initials: M
authors.lastname: Husain
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059445:Anhedonia / Q000145:classification / Q000502:physiology; D057565:Apathy / Q000145:classification* / Q000502:physiology; D003863:Depression / Q000145:classification / Q000453:epidemiology / Q000523:psychology; D004644:Emotions; D005221:Fatigue / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation / Q000502:physiology*; D010555:Personality Inventory; D011594:Psychometrics; D012919:Social Behavior; D055815:Young Adult