Depression You are NOT alone.   Behavioral Definitions:   Loss of appetite and depressed affect. Diminished interest in or enjoyment of activities. Sleeplessness or hypersomnia. Lack of energy, poor concentration and indecisiveness. Social withdrawal. Feelings of hopelessness, worthlessness, or inappropriate guilt. Low self-esteem. Long-Term Goal:   Alleviate depressed mood and return to previous level of effective functioning.