 SCD-WELL includes both an active comparison condition and a 16-week follow up assessment after the end of the intervention. SCD-WELL is a non-CTIMP European multicentre, observer-blinded, randomized, controlled, superiority trial with two parallel groups, which compares anxiety and additional behavioural and biological outcomes amongst people with SCD who receive mindfulness-based training and those who receive a health education comparison intervention. Outcomes will be measured at baseline, post-intervention and 16 weeks after the end of the intervention. 