title: Pharmacovigilance from social media: mining adverse drug reaction mentions using sequence labeling with word embedding cluster features.
abstract: OBJECTIVE
  Social media is becoming increasingly popular as a platform for sharing personal health-related information. This information can be utilized for public health monitoring tasks, particularly for pharmacovigilance, via the use of natural language processing (NLP) techniques. However, the language in social media is highly informal, and user-expressed medical concepts are often nontechnical, descriptive, and challenging to extract. There has been limited progress in addressing these challenges, and thus far, advanced machine learning-based NLP techniques have been underutilized. Our objective is to design a machine learning-based approach to extract mentions of adverse drug reactions (ADRs) from highly informal text in social media.
  
  
  METHODS
  We introduce ADRMine, a machine learning-based concept extraction system that uses conditional random fields (CRFs). ADRMine utilizes a variety of features, including a novel feature for modeling words' semantic similarities. The similarities are modeled by clustering words based on unsupervised, pretrained word representation vectors (embeddings) generated from unlabeled user posts in social media using a deep learning technique.
  
  
  RESULTS
  ADRMine outperforms several strong baseline systems in the ADR extraction task by achieving an F-measure of 0.82. Feature analysis demonstrates that the proposed word cluster features significantly improve extraction performance.
  
  
  CONCLUSIONS
  It is possible to extract complex medical concepts, with relatively high performance, from informal, user-generated content. Our approach is particularly scalable, suitable for social media mining, as it relies on large volumes of unlabeled data, thus diminishing the need for large, annotated training data sets.
authors.affiliation: Department of Biomedical Informatics, Arizona State University, Scottsdale, AZ, USA anikfarj@asu.edu graciela.gonzalez@asu.edu.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Nikfarjam
authors.affiliation: Department of Biomedical Informatics, Arizona State University, Scottsdale, AZ, USA.
authors.forename: Abeed
authors.initials: A
authors.lastname: Sarker
authors.affiliation: Department of Biomedical Informatics, Arizona State University, Scottsdale, AZ, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: O'Connor
authors.affiliation: Department of Biomedical Informatics, Arizona State University, Scottsdale, AZ, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Ginn
authors.affiliation: Department of Biomedical Informatics, Arizona State University, Scottsdale, AZ, USA anikfarj@asu.edu graciela.gonzalez@asu.edu.
authors.forename: Graciela
authors.initials: G
authors.lastname: Gonzalez
mesh_terms: D001185:Artificial Intelligence; D057225:Data Mining / Q000379:methods*; D006801:Humans; D009323:Natural Language Processing; D060735:Pharmacovigilance; D012660:Semantics; D061108:Social Media
keywords: ADR; adverse drug reaction; deep learning word embeddings; machine learning; natural language processing; pharmacovigilance; social media mining