Depression is related to Severe. Severe is a synonym of Intense. Intense is similar to Terrific. 
you are likely to find Study in/at/on Journal. Population can be used for Study. Population is a synonym of Universe. you are likely to find Light in/at/on Universe. 
Depression <--RelatedTo--> Severe <--Synonym--> Intense <--SimilarTo--> Terrific 
Journal <--AtLocation-- Study <--UsedFor-- Population <--Synonym--> Universe <--AtLocation-- Light 