Noticeable change of appetite, with either significant weight loss not attributable to dieting or weight gain.
Noticeable change in sleeping patterns, such as fitful sleep, inability to sleep, early morning awakening, or sleeping too much.
Loss of interest and pleasure in activities formerly enjoyed.
Loss of energy, fatigue.
Feelings of worthlessness.
Persistent feelings of hopelessness.
Feelings of inappropriate guilt.
Inability to concentrate or think, indecisiveness.
Recurring thoughts of death or suicide, wishing to die, or attempting suicide. (Note: People suffering this symptom should receive treatment immediately!)
Melancholia (defined as overwhelming feelings of sadness and grief), accompanied by waking at least two hours earlier than normal in the morning, feeling more depressed in the morning, and moving significantly more slowly.
Disturbed thinking, a symptom developed by some severely depressed persons. For example, severely depressed people sometimes have beliefs not based in reality about physical disease, sinfulness, or poverty.
Physical symptoms, such as headaches or stomachaches.