"This dissertation examines two perspectives on active music-making: Music performance anxiety (MPA) among musicians from different backgrounds and the effects of music-making on seniors' health and wellbeing. The research questions investigated (a) the extent to which performing music yields biological, psychological and social benefits and (b) the extent to which specific biological, psychological and social parameters influence MPA. Using the Biopsychosocial model (Engel, 1980), it was hypothesized that MPA would yield detrimental effects on musicians' wellbeing, whereas music-making would generate multiple benefits that could contribute to promote people's quality of life and healthy aging. Three studies were conducted for this doctoral thesis. The first study, in Chapter 4, provided a new version of the Performance Anxiety Inventory for Musicians (PerfAIM) and described its validation process. The psychometric properties of the PerfAIM were at first estimated with a sample of 69 musicians. After revision and translation, an exploratory factor analysis was carried out with a sample of 241 musicians that revealed four factors (1- Unpredictability; 2- Anticipation; 3- Threat to the ego; 4- Sense of control) explaining over 52% of the variance when combined. The second study, in Chapter 5, investigated the extent to which MPA affected cohorts of musicians performing classical music only, popular music only, or both styles of music. Significant differences were found in MPA between women and men; younger and older performers; people with generalized anxiety and those without; vocalists/arched string players and plucked string/woodwind/brass players, the former reporting higher MPA than the latter. Solo performance setting was considered the most stressful situation, and small ensemble setting the least stressful. Advanced musicians reported more MPA than expert musicians. Classical musicians indicated higher MPA than popular performers and musicians playing both styles. The aim of the third study, in Chapter 6, was to verify the effects of active music-making on beginner musicians aged 60 years old and over by exploring health-related benefits as well as the potentially deleterious impact of MPA during a concert. An experimental and a control group were followed over 15 weeks. The findings indicated that parameters associated with biological, psychological, and social factors mediated the musicians' levels of MPA and yielded positive outcomes for older adults participating in a community band. This thesis contributes to the field of music education in many ways. First, it offers the first questionnaire on MPA validated for classical and popular musicians in both English and French. Second, it provides valuable insights on MPA, including a comparison of multiple parameters (i.e. gender, age, trait anxiety, years of training, instrument, level of expertise, and performance settings) from the perspective of musicians playing different musical styles. Third, it reports new findings on older adults' perception of the initial phases of music learning and describes the impact of MPA in elderly beginner performers. On a practical level, the findings are discussed from a pedagogical perspective and applications to musicians are suggested. " --