Social media has grown to be a crucial information source for
pharmacovigilance studies where an increasing number of people post adverse
reactions to medical drugs that are previously unreported. Aiming to
effectively monitor various aspects of Adverse Drug Reactions (ADRs) from
diversely expressed social medical posts, we propose a multi-task neural
network framework that learns several tasks associated with ADR monitoring with
different levels of supervisions collectively. Besides being able to correctly
classify ADR posts and accurately extract ADR mentions from online posts, the
proposed framework is also able to further understand reasons for which the
drug is being taken, known as 'indication', from the given social media post. A
coverage-based attention mechanism is adopted in our framework to help the
model properly identify 'phrasal' ADRs and Indications that are attentive to
multiple words in a post. Our framework is applicable in situations where
limited parallel data for different pharmacovigilance tasks are available.We
evaluate the proposed framework on real-world Twitter datasets, where the
proposed model outperforms the state-of-the-art alternatives of each individual
task consistently.Comment: Accepted in the research track of The Web Conference(WWW) 201