 I am Dr. Murali Raj. I am currently head of department of psychiatry here and I practice clinical psychiatry at the Manipal Hospital. There are several ways of looking at depression but I think the easiest way of classifying depression is into major or minor depressions. The older classification called it as endogenous and reactive depression. What it basically means is that some depressions are due to light stresses such as losing somebody, loss in job, having had to shift your family totally, being away from others. The other type of depression known as endogenous depression was believed to be due to ease due to changes in brain chemicals and neurotransmitters such as 5-hetero-hydroxy-tryptamine. The present classification focuses on the severity of depression. Depressions are divided into major and minor depressions or major depression in these timing disorders depending on how severe they are. Either way, moderate to severe depressions need to be treated and treated as fast as possible.