Addison's disease is where the adrenal glands that sit on top of your kidneys do not produce enough hormones.
Early symptoms of Addison's disease include lack of energy, weakness, increased thirst and a low mood. The symptoms can get gradually worse over time.
Addison's disease is usually caused by a problem with your immune system.
Treatment for Addison's disease usually involves taking hormones to replace the ones not produced by your adrenal glands.