title: The prevalence of neuropsychiatric symptoms in Alzheimer's disease: Systematic review and meta-analysis.
abstract: BACKGROUND
  Neuropsychiatric symptoms (NPS) are being increasingly recognized as common serious problems in Alzheimer's disease (AD). However, published data on the prevalence of NPS in persons with AD are conflicting. This meta-analysis aimed to estimate the prevalence of NPS in persons with AD.
  
  
  METHODS
  Studies published from 1964 to September 30, 2014, were identified from PubMed and Embase database, reference lists and conference abstracts. We calculated prevalence rates and conducted meta-regression analysis with random-effects model, according to study characteristics, population demographics or condition information.
  
  
  RESULTS
  We identified 48 eligible articles, which provided data for 12 NPS reported in Neuropsychiatric Inventory (NPI). The most frequent NPS was apathy, with an overall prevalence of 49% (95% CI 41-57%), followed by depression, aggression, anxiety and sleep disorder, the pooled prevalence estimates of which were 42% (95% CI 37-46%), 40% (95% CI 33-46%), 39% (95% CI 32-46%) and 39% (95% CI 30-47%), respectively. The less prevalent NPS were irritability (36%, 31-41%), appetite disorder (34%, 27-41%), aberrant motor behavior (32%, 25-38%), delusion (31%, 27-35%), disinhibition (17%, 12-21%) and hallucination (16%, 13-18%). Least common was euphoria, with an overall prevalence of 7% (95% CI 5-9%).
  
  
  CONCLUSIONS
  Several aspects, such as the quality of included studies were not always optimal and there was significant heterogeneity of prevalence estimate across studies.
  
  
  CONCLUSIONS
  NPS were observed to be highly prevalent in AD patients. Disease duration, age, education level, population origin and the severity of cognitive impairment had influence on the prevalence of some NPS.
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Qing-Fei
authors.initials: QF
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China; Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China; College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China. Electronic address: dr.tanlan@163.com.
authors.forename: Lan
authors.initials: L
authors.lastname: Tan
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China.
authors.forename: Hui-Fu
authors.initials: HF
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China.
authors.forename: Teng
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Meng-Shan
authors.initials: MS
authors.lastname: Tan
authors.affiliation: College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Tan
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Jie-Qiong
authors.initials: JQ
authors.lastname: Li
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Psychiatry, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Te-Jen
authors.initials: TJ
authors.lastname: Lai
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China; Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China; College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China; Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA. Electronic address: jintai.yu@ucsf.edu.
authors.forename: Jin-Tai
authors.initials: JT
authors.lastname: Yu
mesh_terms: D000374:Aggression; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000523:psychology*; D001007:Anxiety / Q000453:epidemiology*; D057565:Apathy; D015897:Comorbidity; D003702:Delusions / Q000453:epidemiology*; D003863:Depression / Q000453:epidemiology*; D005059:Euphoria; D001068:Feeding and Eating Disorders / Q000453:epidemiology*; D006212:Hallucinations / Q000453:epidemiology*; D006801:Humans; D007508:Irritable Mood; D015995:Prevalence; D012893:Sleep Wake Disorders / Q000453:epidemiology*
keywords: Alzheimer's disease; Meta-analysis; Neuropsychiatric symptoms; Prevalence