The investigators hypothesize that compared to treatment-as-usual, the add-on of MBCT will result in improved psychological (anxiety, depression) and physical outcomes (physical health status, activity level, inflammatory markers). Furthermore, the investigators will explore the possible moderating role of individual differences in sociodemographic and disease-related characteristics and the perceived quality of the therapeutic alliance, as well as the mediating role of mindfulness, breathlessness catastrophizing, self-efficacy, and self-compassion for the hypothesised effect.