title: Classification of Neuropsychiatric Symptoms Requiring Antipsychotic Treatment in Patients with Alzheimer's Disease: Analysis of the CATIE-AD Study.
abstract: BACKGROUND
  The Neuropsychiatric Inventory (NPI) comprises 12 items, which were conventionally determined by psychopathological symptoms of patients with dementia. The clinical rating scales with structured questionnaires have been useful to evaluate neuropsychiatric symptoms (NPSs) of patients with dementia over the past twenty year.
  
  
  OBJECTIVE
  The aim of this study was to classify the conventional NPSs in patients with Alzheimer's disease (AD) requiring antipsychotic treatment for their NPSs into distinct clusters to simplify assessment of these numerous symptoms.
  
  
  METHODS
  Twelve items scores (product of severity and frequency of each symptom) in the NPI taken from the baseline visit were classified into subgroups by principle component analysis using data from 421 outpatients with AD enrolled in the Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer's Disease (CATIE-AD) Phase 1. Chi square tests were conducted to examine the co-occurrence of the subgroups.
  
  
  RESULTS
  We found four distinct clusters: aggressiveness (agitation and irritabilities), apathy and eating problems (apathy and appetite/eating disturbance), psychosis (delusions and hallucinations), and emotion and disinhibition (depression, euphoria, and disinhibition). Anxiety, aberrant motor behavior, and sleep disturbance were not included by these clusters. Apathy and eating problems, and emotion and disinhibition co-occurred (p = 0.002), whereas aggressiveness and psychosis occurred independent of the other clusters.
  
  
  CONCLUSIONS
  Four distinct category clusters were identified from NPSs in patients with AD requiring antipsychotic treatment. Future studies should investigate psychosocial backgrounds or risk factors of each distinct cluster, in addition to their longitudinal course over treatment intervention.
authors.affiliation: Department of Psychiatry, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nagata
authors.affiliation: Department of Psychiatry, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Shunichiro
authors.initials: S
authors.lastname: Shinagawa
authors.affiliation: Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan.|Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada.|Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada.|Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Nakajima
authors.affiliation: Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada.|Institute of Medical Science, University of Toronto, Toronto, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Plitman
authors.affiliation: Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Mihashi
authors.affiliation: Department of Anatomy, Tokyo Medical University, Tokyo, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Mimura
authors.affiliation: Department of Psychiatry, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000374:Aggression; D000544:Alzheimer Disease / Q000150:complications*; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D057565:Apathy; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D011595:Psychomotor Agitation; D011618:Psychotic Disorders / Q000145:classification / Q000188:drug therapy / Q000209:etiology; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D014150:Antipsychotic Agents
keywords: Alzheimer’s disease; delusions; neuropsychiatric symptoms; principal component analysis