Depression is described as feeling sad, blue, unhappy, miserable, or down. Some signs of depression include feeling hopeless, loss of interest in activities, difficulties sleeping, excessive thinking about mistakes, and thoughts of suicide. Physical symptoms can include changes in appetite, fatigue, aches and pains, and feelings of emptiness. There are several types of depression including anxiety disorders, bipolar disorder, depression related to physical illness, and seasonal affective disorder. Rates of depression are increasing, with 15% of developed countries experiencing severe depression and 30% of women experiencing depression.