Depression is a complex condition, and because it affects so many systems of the body, it has many manifestations, which can greatly vary from one person to the next. In general, symptoms include: • Feelings of sadness, emptiness, or hopelessness • Irritability, angry outbursts, or low frustration tolerance • Loss of interest in activities that were once enjoyable, from sports to sex • Sleep disturbance, including not sleeping enough, or sleeping too much • Fatigue/lack of energy; everything feels effortful • Appetite disturbance, including overeating or loss of interest in eating • Anxiety, agitation, and restlessness • Slowed thinking, moving, or talking • Feelings of worthlessness and guilt • A focus on past failure, self-blame • Difficulty concentrating, remembering things, and making decisions • Recurring thoughts of death • Physical pain such as headaches, back pain