There are many types of thyroid disease. The main conditions present in most thyroid illnesses are hypothyroidism (thyroid under activity) and hyperthyroidism (thyroid over activity). Thyroid problems are more common in older women than in men. Thyroid patients require life-long monitoring. Hyperthyroid patients often feel unusually nervous or irritable. Hypothyroid patients can feel unusual fatigue or depression. It is important for thyroid patients and their families to understand that these reactions are common and likely to resolve with treatment. It is also important to realize that some thyroid disorders develop very gradually and it can take a while before they disappear after treatment has been initiated. Since symptoms may not be easily recognized at first, subtle reactions in emotions or behaviour may be the only visible signs of thyroid disorder.