Sure, most of us feel sad, lonely, or depressed at times. And feeling depressed is a normal reaction to loss, life's struggles, or an injured self-esteem. But when these feelings become overwhelming, involve physical symptoms, and last for long periods of time, they can keep you from leading a normal, active life.

• Persistently sad, anxious, or empty moods
• Loss of pleasure in usual activities (anhedonia)
• Feelings of helplessness, guilt, or worthlessness
• Crying, hopelessness, or persistent pessimism
• Fatigue or decreased energy
• Loss of memory, concentration, or decision-making capability
• Restlessness, irritability
• Sleep disturbances
• Change in appetite or weight
• Physical symptoms that defy diagnosis and do not respond to treatment (especially pain and gastrointestinal complaints)
• Thoughts of suicide or death, or suicide attempts
• Poor self-image or self-esteem (as illustrated, for example, by verbal self-reproach)
• There are no inevitable physical signs of depression, though some manifestations may be seen quite often. Signs of depression may include the following