Recent studies have highlighted the differences between the three generations of cognitive behavioral therapy starting from behavioral therapy to arrive to cognitive therapy and the third-generation principles (Hayes e coll., 2013). This article describes a view of symptoms through the models of cognitive behavioral therapy and their evolution in time. With the help of examples of dialogue between a therapist and a young patient, the author describes the theory and the basic principles of behavioral therapy, the development of the concepts related to cognitivism, the techniques and components that link them to the third-generation and its key processes. From this emerge the importance of direct observation and the empirical validation of symptoms, attention for thoughts, different levels of analysis in time and the study of the role of variables in the context while expanding the epistemological basis of what is considered a symptom in the latest generation of cognitive behavioral scholars.
Keywords: Symptoms, cognitive behavioral therapy, epistemology