  Suicide is among the leading causes of death in China. However, technical
approaches toward preventing suicide are challenging and remaining under
development. Recently, several actual suicidal cases were preceded by users who
posted microblogs with suicidal ideation to Sina Weibo, a Chinese social media
network akin to Twitter. It would therefore be desirable to detect suicidal
ideations from microblogs in real-time, and immediately alert appropriate
support groups, which may lead to successful prevention. In this paper, we
propose a real-time suicidal ideation detection system deployed over Weibo,
using machine learning and known psychological techniques. Currently, we have
identified 53 known suicidal cases who posted suicide notes on Weibo prior to
their deaths.We explore linguistic features of these known cases using a
psychological lexicon dictionary, and train an effective suicidal Weibo post
detection model. 6714 tagged posts and several classifiers are used to verify
the model. By combining both machine learning and psychological knowledge, SVM
classifier has the best performance of different classifiers, yielding an
F-measure of 68:3%, a Precision of 78:9%, and a Recall of 60:3%.
