According to DSM-V, five of the following symptoms have to be present for the past 2-week period and cause a change from previous functioning, at least one of the symptoms is either depressed mood or loss of interest or pleasure. 1. Feeling empty, sad, hopeless or easily tearful. 2. Markedly diminished interest or pleasure in activities most of the day, every day. 3. Significant weight loss or weight gain. 4. Lack of sleep or excessive sleeping. 5. Loss of energy and fatigue all the time. 6. Excessive feeling of inappropriate guilt and worthlessness all the time. 7. Diminished ability to think, concentrate or make clear decisions. 8. Recurrent thoughts of death, suicidal ideation without a specific plan, or an attempt of suicide, or having a specific plan of suicide.
The symptoms are causing clinical significant distress and impairment in social, occupational, or other areas of functioning. The symptoms are not due to substance abuse, or any other medical conditions. If you are experiencing these symptoms, please seek professional help.
Information copied from DSM-V