Depression is a type of Hell. Depression is a type of Mood. Mood is related to Emotion. Emotion is related to Comfort. 
Guitar is a type of Instrument. you are likely to find Guitar in/at/on Concert. you are likely to find Artist in/at/on Concert. 
Hell <--IsA-- Depression --IsA--> Mood <--RelatedTo--> Emotion <--RelatedTo--> Comfort 
Instrument <--IsA-- Guitar --AtLocation--> Concert <--AtLocation-- Artist 