title: Association between symptom dimensions and categorical diagnoses of psychosis: a cross-sectional and longitudinal investigation.
abstract: BACKGROUND
  Cross-sectional studies of the signs and symptoms of psychosis yield dimensional phenotypes. However, the validity and clinical utility of such dimensions remain debated. This study investigated the structure of psychotic symptomatology, the stability of the structure over time, and the concordance between symptom dimensions and categorical diagnoses.
  
  
  METHODS
  Sample consisted of 500 first-episode psychotic patients. A cross-sectional study (N = 500) investigated the organizational structure of symptom dimensions at the onset of psychosis and its concordance with categorical diagnoses; next, a nested longitudinal study (N = 100) examined the stability of the symptom dimensions structure after 5-10 years of follow-up.
  
  
  RESULTS
  Factor analyses identified 6 first-order factors (mania, negative, disorganization, depression, hallucinations, and delusions) and 2 high-order factors (affective and nonaffective psychoses). Cumulative variance accounted for by the first and high-order factors was 63%: 31% by the first-order factors and 32% by the high-order factors. The factorial structure of psychotic symptoms during first episode remained stable after 5-10 years of follow-up. The overall concordance between 4 categorical diagnostic groups (schizophrenia, mania with psychosis, psychotic depression and schizoaffective disorder) and dimensional symptom ranged from 62.2% to 73.1% (when the schizoaffective group was excluded).
  
  
  CONCLUSIONS
  Symptoms of psychosis assume a multidimensional hierarchical structure. This hierarchical model was stable over time and showed good concordance with categorical diagnoses. The combined use of dimensional and categorical approach to psychotic disorders would be of clinical and research utility.
authors: The work was carried out at the Department of Psychosis Studies, Institute of Psychiatry, King's College London.
authors: Manuela
authors: M
authors: Russo
authors: Stephen Z
authors: SZ
authors: Levine
authors: Arsime
authors: A
authors: Demjaha
authors: Marta
authors: M
authors: Di Forti
authors: Stefania
authors: S
authors: Bonaccorso
authors: Paul
authors: P
authors: Fearon
authors: Paola
authors: P
authors: Dazzan
authors: Carmine M
authors: CM
authors: Pariante
authors: Anthony S
authors: AS
authors: David
authors: Craig
authors: C
authors: Morgan
authors: Robin M
authors: RM
authors: Murray
authors: Abraham
authors: A
authors: Reichenberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001526:Behavioral Symptoms / Q000145:classification*; D003430:Cross-Sectional Studies; D005163:Factor Analysis, Statistical; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D025341:Principal Component Analysis; D011618:Psychotic Disorders / Q000145:classification* / Q000503:physiopathology; D055815:Young Adult
keywords: DSM-5; diagnostic classification; longitudinal study; psychosis; symptom dimensions
references: Br J Psychiatry. 1980 Oct;137:383-6
references: 7448479
references: Int J Methods Psychiatr Res. 2007;16 Suppl 1:S1-5
references: 17623390
references: Br J Psychiatry. 1996 Sep;169(3):371-8
references: 9004982
references: Psychol Med. 2009 Dec;39(12):1943-55
references: 19627645
references: Br J Psychiatry. 2005 May;186:369-77
references: 15863740
references: Schizophr Bull. 2006 Jan;32(1):9-16
references: 16319375
references: Schizophr Res. 2004 Dec 1;71(2-3):405-16
references: 15474912
references: Psychol Med. 1999 May;29(3):595-606
references: 10405080
references: Arch Gen Psychiatry. 2006 Mar;63(3):250-8
references: 16520429
references: Schizophr Res. 2010 Feb;116(2-3):234-42
references: 19751968
references: Arch Gen Psychiatry. 1995 May;52(5):352-60
references: 7726715
references: Arch Gen Psychiatry. 1982 Jul;39(7):789-94
references: 7165478
references: Psychol Med. 1998 Jul;28(4):935-47
references: 9723148
references: Lancet. 2009 Aug 22;374(9690):635-45
references: 19700006
references: J Clin Psychol. 2009 Aug;65(8):879-90
references: 19536867
references: Curr Opin Psychiatry. 2007 Jul;20(4):365-79
references: 17551352
references: Mol Psychiatry. 2006 Sep;11(9):815-36
references: 16801952
references: Psychopathology. 2008;41(4):264-70
references: 18441528
references: Schizophr Bull. 2007 Jul;33(4):861-2
references: 17545204
references: Eur Psychiatry. 2002 Oct;17(6):311-20
references: 12457741
references: Am J Psychiatry. 2011 Nov;168(11):1186-94
references: 21676994
references: Schizophr Bull. 2009 Sep;35(5):857-8
references: 19617356
references: Br J Psychiatry. 1987 Aug;151:145-51
references: 3690102
references: Schizophr Res. 1999 Sep 29;39(2):153-8; discussion 163
references: 10507527
references: Br J Psychiatry. 2005 Dec;187:516-22
references: 16319403
references: Soc Psychiatry Psychiatr Epidemiol. 2007 Jun;42(6):429-37
references: 17502977
references: Am J Med. 2007 Apr;120(4 Suppl 1):S26-31
references: 17403379
references: Schizophr Bull. 1987;13(2):261-76
references: 3616518
references: Schizophr Bull. 2008 Jan;34(1):109-17
references: 17515440
references: Schizophr Bull. 2011 Nov;37(6):1136-46
references: 21857008
references: Behav Res Methods. 2005 Feb;37(1):48-58
references: 16097343
references: Schizophr Res. 2001 Dec 1;52(3):215-29
references: 11705715
references: Psychol Med. 1975 May;5(2):181-92
references: 1161956
references: Arch Gen Psychiatry. 1990 Jun;47(6):589-93
references: 2190539