Depression often involves persistent sad, anxious, or empty mood; feelings of hopelessness or pessimism; and feelings of guilt, worthlessness, or helplessness. It can also involve loss of interest or pleasure in hobbies and activities that were once enjoyed, including sex. Decreased energy, fatigue, or a sense of being “slowed down” are also common, as are restlessness, irritability, and difficulty concentrating, remembering, or making decisions. Many with depression have thoughts of death or suicide.