What are the most common signs of depression?

•difficulty concentrating, remembering details, and making decisions
•fatigue and decreased energy
•feelings of guilt, worthlessness, and/or helplessness
•feelings of hopelessness and/or pessimism
•insomnia, early-morning wakefulness, or excessive sleeping
•irritability, restlessness
•loss of interest in activities or hobbies once pleasurable, including sex
•overeating or appetite loss
•persistent aches or pains, headaches, cramps, or digestive problems that do not ease even with treatment
•persistent sad, anxious, or "empty" feelings
•thoughts of suicide, suicide attempts