Is Drake's Kid Cudi depression diss a step too far?

From Jay Z and Nas’s feud to Eminem’s persistent mom-bashing, diss tracks have taken things to the extreme, but recent attacks may be stepping over the lineIs there a limit to what can be deemed suitable for rap disses? Should there be? What, if anything, crosses the line into outright abuse? Recent squabbling between Drake and Kid Cudi has dredged up some talk surrounding mental illness, and has many listeners calling foul.In a song called Two Birds, One Stone, Drake took aim at lon