title: Antipsychotic treatment resistance in first-episode psychosis: prevalence, subtypes and predictors.
abstract: BACKGROUND
  We examined longitudinally the course and predictors of treatment resistance in a large cohort of first-episode psychosis (FEP) patients from initiation of antipsychotic treatment. We hypothesized that antipsychotic treatment resistance is: (a) present at illness onset; and (b) differentially associated with clinical and demographic factors.
  
  
  METHODS
  The study sample comprised 323 FEP patients who were studied at first contact and at 10-year follow-up. We collated clinical information on severity of symptoms, antipsychotic medication and treatment adherence during the follow-up period to determine the presence, course and predictors of treatment resistance.
  
  
  RESULTS
  From the 23% of the patients, who were treatment resistant, 84% were treatment resistant from illness onset. Multivariable regression analysis revealed that diagnosis of schizophrenia, negative symptoms, younger age at onset, and longer duration of untreated psychosis predicted treatment resistance from illness onset.
  
  
  CONCLUSIONS
  The striking majority of treatment-resistant patients do not respond to first-line antipsychotic treatment even at time of FEP. Clinicians must be alert to this subgroup of patients and consider clozapine treatment as early as possible during the first presentation of psychosis.
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: A
authors.initials: A
authors.lastname: Demjaha
authors.affiliation: School of Psychiatry, University of New South Wales, Sydney, NSW,Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Lappin
authors.affiliation: Department of Biostatistics,Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: D
authors.initials: D
authors.lastname: Stahl
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: M X
authors.initials: MX
authors.lastname: Patel
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: J H
authors.initials: JH
authors.lastname: MacCabe
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: O D
authors.initials: OD
authors.lastname: Howes
authors.affiliation: Health Service and Population Research Department,Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: M
authors.initials: M
authors.lastname: Heslin
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: U A
authors.initials: UA
authors.lastname: Reininghaus
authors.affiliation: Addictions Department,Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: K
authors.initials: K
authors.lastname: Donoghue
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: B
authors.initials: B
authors.lastname: Lomas
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: M
authors.initials: M
authors.lastname: Charalambides
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: A
authors.initials: A
authors.lastname: Onyejiaka
authors.affiliation: Department of Psychiatry,Trinity College,Dublin, Republic ofIreland.
authors.forename: P
authors.initials: P
authors.lastname: Fearon
authors.affiliation: Department of Psychiatry,University of Cambridge,Cambridge,UK.
authors.forename: P
authors.initials: P
authors.lastname: Jones
authors.affiliation: Division of Psychiatry,University of Nottingham,Nottingham,UK.
authors.forename: G
authors.initials: G
authors.lastname: Doody
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: C
authors.initials: C
authors.lastname: Morgan
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: P
authors.initials: P
authors.lastname: Dazzan
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK.
authors.forename: R M
authors.initials: RM
authors.lastname: Murray
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology*; D004351:Drug Resistance / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011618:Psychotic Disorders / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D012559:Schizophrenia / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents
keywords: Clozapine; First-Episode- Psychosis; Schizophrenia; Treatment-Resistant; Treatment-Response