title: A naturalistic longitudinal study of at-risk mental state with a 2.4 year follow-up at a specialized clinic setting in Japan.
abstract: OBJECTIVE
  The notion of at-risk mental state (ARMS) is valuable for identifying individuals in a putative prodromal state of psychosis and for reducing conversion risk by pharmacological and psychological interventions. However, further systematic study is required because 1) diagnostic reliability in various clinical settings is not yet established; 2) predictive ability is insufficient; 3) optimal interventions in diversified populations are elusive; and 4) little evidence from non-Western regions exists.
  
  
  METHODS
  A naturalistic longitudinal study was conducted at a specialized clinic for early psychosis at a university hospital in Sendai, Japan. Individuals with ARMS (n=106) were recruited and followed up with case-by-case treatment.
  
  
  RESULTS
  Two-thirds of the participants were psychiatrist referrals, and 83 were followed up for at-least 1 year (mean follow-up=2.4 years). Fourteen developed psychosis and the estimated (by Kaplan-Meier) cumulative transition rate was 11.1% at 12, 15.4% at 24, and 17.5% at 30 months. At the end-point, about 30% of the 83 followed-up participants including 11 converters received antipsychotic medication. Compared to non-converters, converters showed more severe attenuated psychotic symptoms, including ego-boundary disturbance, formal thought disorder, and emotional disturbance.
  
  
  CONCLUSIONS
  The present study replicated previous major Western longitudinal studies, in terms of clinical characteristics, psychosis transition rate, and antipsychotic prescription rate. Our results emphasize the importance of phenomenological assessment of ARMS and intensive care in a clinical setting.
authors.affiliation: Department of Psychiatry, Tohoku University Hospital, Sendai, Japan. Electronic address: katsura-thk@umin.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Katsura
authors.affiliation: Department of Psychiatry, Tohoku University Hospital, Sendai, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ohmuro
authors.affiliation: Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Obara
authors.affiliation: Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kikuchi
authors.affiliation: Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Psychiatry, Tohoku Pharmaceutical University Hospital, Sendai, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Ito
authors.affiliation: Chiba Prison, Chiba, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Miyakoshi
authors.affiliation: Department of Psychiatry, Tohoku University Hospital, Sendai, Japan; Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Hiroo
authors.initials: H
authors.lastname: Matsuoka
authors.affiliation: Department of Psychiatry, Tohoku University Hospital, Sendai, Japan; Department of Preventive Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D062706:Prodromal Symptoms; D011618:Psychotic Disorders / Q000188:drug therapy / Q000453:epidemiology* / Q000523:psychology; D012306:Risk; D055815:Young Adult
keywords: Antipsychotics; Clinical high risk; Early intervention; Psychosis; Schizophrenia; Ultra-high risk (UHR)