Burden is a type of Concern. Burden is a synonym of Catch. Catch is a type of Spread. Spread is the opposite of Gather. 
Depression is related to Illness. Shock is a type of Illness. Shock is a type of Collapse. 
Concern <--IsA-- Burden <--Synonym--> Catch --IsA--> Spread <--Antonym--> Gather 
Depression <--RelatedTo--> Illness <--IsA-- Shock --IsA--> Collapse 