Mood changes can range from irritability to anhedonia, the inability to enjoy everyday happenings.
Changes in thought can differ in focus and in concentration, including difficulty remembering things, a sense of hopelessness, or dark thoughts and contemplation of suicide. Shifting sleep patterns, appetite or energy levels may lead to the physical changes caused by depression. We typically look for a cluster of five or six symptoms within these groups. The key is impairment. When depression changes someone's home, work, or social situations, it is a cause for concern.