According to The Diagnostic and Statistical Manual of Mental Health Disorders, Fifth Edition (DSM-V), five or more of the symptoms listed below must be present during the same 2‐week time period that represents changes in functioning. At least one symptom is either a depressed mood or loss of interest.
- Depressed mood most of the day, nearly every day, as indicated in the subjective report or in observation made by others
- Markedly diminished interest in pleasure in all, or almost all, activities most of the day and nearly every day
- Significant weight loss when not dieting or weight gain, for example, more than 5 percent of body weight in a month or changes in appetite nearly every day
- Insomnia or hypersomnia nearly every day
- Psychomotor agitation or retardation nearly every day
- Fatigue or loss of energy nearly every day
- Feelings of worthlessness or excessive or inappropriate guilt
- Diminished ability to think or concentrate, or indecisiveness nearly every day
- Recurrent thoughts of death
Major Depressive Disorder can be classified as mild, moderate, or severe.