[4] However, other studies have shown that symptoms of bipolar disorders persist in patients with hyperthyroidism after their hyperthyroidism has been brought under control with medication. [6], [7] Moreover, another study stressed that residual mood disturbance may exist for a long time even under euthyroid status. [8] There is no doubt that elevated thyroid hormone level has direct effect on mood. This evidence concerns the gene TG and bipolar disorder.