DOES IT MATTER IF THE GLASS IS HALF FULL OR HALF EMPTY?IMPLICATIONS OF DISPOSITIONAL OPTIMISM IN THE GENERAL POPULATION AND IN CANCER PATIENTS

Dispositional optimism is defined as having a generalized positive expectation about the future. It is a personality trait with benefits in different aspects of life: optimists consider the future as an opportunity, cope better with stress and have better physical and mental health. Considering its beneficial effects, dispositional optimism had been studied for many years and by different authors but there are still some open questions about it. This thesis is a contribution in knowing more about this personality trait. The first question that started this work was: how can we measure dispositional optimism? The query brought to a controversy that has its root in the dimensionality of the construct. Some works prove that it is a monodimensional bipolar construct, some others demonstrate that it forms two unipolar dimensions. Our data can be added to the list of works that confirm the monodimensionality of optimism. After having found firsthand proof about the dimensionality of dispositional optimism, the following projects part of this thesis all considered the personality trait as monodimensional. Another question about dispositional optimism is whether optimists really think in a more positive manner or not. By analyzing individuals’ new year resolutions, the second study of this thesis was able to confirm that optimists do think and write in a more positive way compared to their negative counterparts. But is optimism always positive? Or does it have a dark side? Some authors reported that dispositional optimism is associated with risk perception. However, the results of this thesis go opposite to this theory: dispositional optimists do not risk more than pessimists, indeed, our results confirmed that optimists did not surrender in face of adversities, but they put any effort in trying to make adversities better. Considering its beneficial effects, the following question to be answered was whether optimism has some impact on a vulnerable population such as cancer patients. This query led to a systematic review of the literature on the subject. The results of the included studies confirmed that dispositional optimism does have a relationship with the quality of life of cancer patients. The previously described works opened the possibility to another perspective: if dispositional optimist is a personality trait with beneficial effects, and knowing that it has a positive impact also on cancer patients’ quality of life, can we improve dispositional optimism in cancer patients? This is the last question of this project. The empirical contribution could not confirm the efficacy of two interventions to enhance dispositional optimism, but it confirmed the relationship between quality of life and dispositional optimism of cancer patients. In conclusion, this thesis is a contribution in answering some questions about dispositional optimism and it highlights the importance to focus attention on dispositional optimism applied into the oncological setting.