An autoimmune disease where the thyroid is overactive, producing an excessive amount of thyroid hormones (a serious metabolic imbalance known as hyperthyroidism and thyrotoxicosis). This is caused by autoantibodies to the TSH-receptor (TSHR-Ab) that activate that TSH-receptor (TSHR), thereby stimulating thyroid hormone synthesis and secretion, and thyroid growth (causing a diffusely enlarged goiter). The resulting state of hyperthyroidism can cause a dramatic constellation of neuropsychological and physical signs and symptoms, which can severely compromise the patients. [ HPO:sdoelken ]