Pires, António Augusto PazoVeiga, Gonçalo Marmelo da Silva2020-01-312020-01-312019-12-10http://hdl.handle.net/10400.12/7372Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Psicologia Clínica.In this study we explore the application of sentiment analysis to a complete and in-person psychotherapy session. Sentiment analysis is a text mining technique that allows for the analysis, interpretation, and visualization of textual data. We investigate how we can apply a lexicon-based approach to analyze clinical session data, using four general-purpose lexicons available within an open-source statistical programming language environment, R. We conducted our study by comparing the performance of four general-purpose lexicons to the performance of n = 52 human raters, using inter-rater reliability (IRR) and intraclass correlation (ICC) measurements. Our findings suggest there is low to moderate agreement between human ratings and lexicon generated ratings, depending on the lexicon used. There are some benefits in applying a lexicon-based sentiment analysis approach to psychotherapy session data, namely the way it efficiently processes and analyses data and allows for novel visualizations of psychotherapy data. We recommend further investigation into the application of sentiment analysis as a technique, focusing on the performance of specific-purpose lexicons. We also recommend further research into comparing the performance of lexicon-based approaches to text classification approaches to the analysis of psychotherapy data.engSentiment analysisLexicon-based approachTherapy session dataDicionário de termosAnálise de sentimentoDados clínicos de psicoterapiamaster thesis202349489