Depression is viewed as the largest contributor to global disability and a major reason for suicide. It has an impact on the language usage reflected in the written text. The key objective of our study is to examine Reddit users’ posts to detect any factors that may reveal the depression attitudes of relevant online users. For such purpose, we employ the Natural Language Processing (NLP) techniques and machine learning approaches to train the data and evaluate the efficiency of our proposed method. We identify a lexicon of terms that are more common among depressed accounts. The results show that our proposed method can significantly improve performance accuracy. The best single feature is bigram with the Support Vector Machine (SVM) classifier to detect depression with 80% accuracy and 0.80 F1 score. The strength and effectiveness of the combined features (LIWC+LDA+bigram) are most successfully demonstrated with the Multilayer Perceptron (MLP) classifier resulting in the top performance for depression detection reaching 91% accuracy and 0.93 F1 score. According to our study, better performance improvement can be achieved by proper feature selections and their multiple feature combinations.

Suicide ideation expressed in social media has an impact on language usage. Many at-risk individuals use social forum platforms to discuss their problems or get access to information on similar tasks. The key objective of our study is to present ongoing work on automatic recognition of suicidal posts. We address the early detection of suicide ideation through deep learning and machine learning-based classification approaches applied to Reddit social media. For such purpose, we employ an LSTM-CNN combined model to evaluate and compare to other classification models. Our experiment shows the combined neural network architecture with word embedding techniques can achieve the best relevance classification results. Additionally, our results support the strength and ability of deep learning architectures to build an effective model for a suicide risk assessment in various text classification tasks.

With the development of social networks, a large variety of approaches have been developed to define users’ personalities based on their social activities and language use habits. Particular approaches differ with regard to different machine learning algorithms, data sources and feature sets. The goal of this paper is to investigate the predictability of the personality traits of Facebook users based on different features and measures of the Big 5 model. We examine the presence of structures of social networks and linguistic features relative to personality interactions using the myPersonality project dataset. We analyse and compare four machine learning models and perform the correlation between each of the feature sets and personality traits. The results for the prediction accuracy show that even if tested under the same dataset, the personality prediction system built on the XGBoost classifier outperforms the average baseline for all the feature sets, with a highest prediction accuracy of 74.2%. The best prediction performance was reached for the extraversion trait by using the individual Social Network Analysis (SNA) features set, which achieved a higher personality prediction accuracy of 78.6%.

The determination of semantic similarity between sentences is an important component in natural language processing (NLP) tasks such as text retrieval and text summarization. Many approaches have been proposed for estimating sentence similarity, and Siamese neural networks (SNN) provide a better approach. However, the sentence semantic representation, generated by sharing weights in the SNN without any attention mechanism, ignores the different contributions of different words to the overall sentence semantics. Furthermore, the attention operation within only a single sentence neglects interactive semantic influence on similarity estimation. To address these issues, an interactive self-attention (ISA) mechanism is proposed in this paper and integrated with an SNN, named an interactive self-attentive Siamese neural network (ISA-SNN) which is used to verify the effectiveness of ISA. The proposed model obtains the weights of words in a single sentence by means of self-attention and extracts inherent interactive semantic information between sentences via interactive attention to enhance sentence semantic representation. It achieves better performances without feature engineering than other existing methods on three biomedical benchmark datasets (a Pearson correlation coefficient of 0.656 and 0.713/0.658 on DBMI and CDD-ful/-ref, respectively).