Several studies in clinical neuroscience have focused on the analysis of expression of emotions, identification of emotions and experience of emotions. These empirical studies produced certain insights into emotional competency in different mental diseases, most of them in schizophrenia. The current article gives a description of the scientific data about alterations in emotional competency in several mental diseases (e.g. schizophrenia, depression, bipolar and borderline diseases) and links the data, if possible, with clinical relevance with a special focus on emotional competency in prodromal schizophrenia.