Mental fatigue (MF) is prevalent after Graves' disease (GD), which is the most common form of hyperthyroidism. We have reported that 38% of patients, compared to 11% of control subjects, suffer from MF more than 1 year after successfully reversing of their hyperthyroidism and that MF is an entity of its own, separated from MF combined with anxiety or depression. The brain pathophysiology is unknown and there is no medical treatment, which requires patients to simply adapt to the situation. In the new national guideline for hyperthyroidism (Jan 2023), rehabilitation is recommended, but currently rarely offered to these patients. The problem is significant for patients, as illustrated by frequent media appeals. In this project, we hypothesise that person-centred care (PCC), which promotes positive coping strategies and increases self-efficacy by engaging patients as partners in their own care, improves MF, reduces sick leave, and lowers the recurrence rate of GD. In two work packages (WP), we will: WP1 Evaluate the effect of PCC eHealth intervention (telephone and digital platform) as an add-on to usual care vs usual care alone in a randomized controlled trial (RCT) of 220 patients on self-efficacy, days of sick-leave (composite score as primary outcome), MF, recurrence rate of disease, coping strategies, perceived stress, quality of life (QoL) and personality. WP2 Investigate the cost-effectiveness of the intervention Patients with GD have impaired long-term QoL. PCC could improve long-term outcomes of this autoimmune disease and may apply to other patient groups. This is in line with the societal aim to reduce mental illness.