It is characterized by 5 of the following for 2 weeks, including depressed mood and anhedonia (inability to attain pleasure from normally pleasurable events or things). 1. Sleep disturbances 2. Loss of Interest 3. Guilt 4. Loss of Energy 5. Loss of Concentration 5. Change in appetite 6. Psychomotor retardation 8. Suicidal ideations 9. Depressed mood. Recurrent Depression- Requires two or more episodes with a symptom free interval of 2 months. Lifetime prevalence- 5 to 12% males; females- 10 to 25%.
Science progresses by questioning the existing dogmas.