title: A network view on psychiatric disorders: network clusters of symptoms as elementary syndromes of psychopathology.
abstract: BACKGROUND
  The vast number of psychopathological syndromes that can be observed in clinical practice can be described in terms of a limited number of elementary syndromes that are differentially expressed. Previous attempts to identify elementary syndromes have shown limitations that have slowed progress in the taxonomy of psychiatric disorders.
  
  
  OBJECTIVE
  To examine the ability of network community detection (NCD) to identify elementary syndromes of psychopathology and move beyond the limitations of current classification methods in psychiatry.
  
  
  METHODS
  192 patients with unselected mental disorders were tested on the Comprehensive Psychopathological Rating Scale (CPRS). Principal component analysis (PCA) was performed on the bootstrapped correlation matrix of symptom scores to extract the principal component structure (PCS). An undirected and weighted network graph was constructed from the same matrix. Network community structure (NCS) was optimized using a previously published technique.
  
  
  RESULTS
  In the optimal network structure, network clusters showed a 89% match with principal components of psychopathology. Some 6 network clusters were found, including "Depression", "Mania", "Anxiety", "Psychosis", "Retardation", and "Behavioral Disorganization". Network metrics were used to quantify the continuities between the elementary syndromes.
  
  
  CONCLUSIONS
  We present the first comprehensive network graph of psychopathology that is free from the biases of previous classifications: a 'Psychopathology Web'. Clusters within this network represent elementary syndromes that are connected via a limited number of bridge symptoms. Many problems of previous classifications can be overcome by using a network approach to psychopathology.
authors.affiliation: Department of Mood Disorders, PsyQ Psychomedical Programs, The Hague, The Netherlands; Parnassia Group, The Hague, The Netherlands.
authors.forename: Rutger
authors.initials: R
authors.lastname: Goekoop
authors.affiliation: Department of Psychiatry, Leiden University Medical Center, Leiden University, Leiden, The Netherlands.
authors.forename: Jaap G
authors.initials: JG
authors.lastname: Goekoop
mesh_terms: D014150:Antipsychotic Agents / Q000627:therapeutic use; D016000:Cluster Analysis; D006801:Humans; D001523:Mental Disorders / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology*; D015233:Models, Statistical; D025341:Principal Component Analysis; D011569:Psychiatric Status Rating Scales; D011599:Psychopathology / Q000379:methods / Q000706:statistics & numerical data*; D063189:Symptom Assessment / Q000379:methods / Q000706:statistics & numerical data*; D009626:Terminology as Topic
chemical_list: D014150:Antipsychotic Agents