The Spanish Tragedy Theme of Madness

There's crazy all over the place in The Spanish Tragedy. In fact, madness is a staple in revenge tragedies. After the popularity of Kyd's exploration of madness and revenge, Shakespeare featured disjointed avengers in both Titus Andronicus and Hamlet. And this trend has continued throughout the genre. But usually it's unclear whether or not avengers really go crazy, or if it's just a tactic. Hieronimoand Hamletboth outwardly say that they're merely adopting a mask of madness to keep their enemies guessing. But as readers, we're like, "dude, you really seem crazy." So the question is this: is madness just a way to create ambiguity so avengers can hide in plain sight? Or does wandering outside of the law to seek blood necessarily make people go cray cray?

1. When exactly does Hieronimo start acting crazy? Is it before or after he announces his plan to "rest […] in unrest" (or act nutty) in Act 3, scene 13? Is madness a well-crafted plan, or is Hieronimo naturally 'coo coo for cocoa puffs?' And since that last reference is from the 70s, here's what we mean.
2. Hieronimo isn't the only crazy bird in the play. What about Balthazar's love madness for Bel-Imperia? And what about Isabella's descent into madness that ends with her taking her anger out on a garden? And what about the Portuguese Viceroy's violent mood swings? Now that we think of it, who are the sane characters in the play? If you think there are any, consider what happens to them as you talk about the consequences of sanity in a crazy world.
3. Is crazy just a matter of context? For example, a character named "Second Portuguese" (yes, there's a first) says about Hieronimo, "Doubtless this man is passing lunatic" (3.13.34). And while he makes this diagnosis based on Hieronimo's ranting and raving, as an audience we understand that his wild speech is totally justified if we consider the context of his son's murder? Is madness in the play just a result of being misunderstood?
4. The last scene of the play is, for lack of a better word, crazy. Forget about the mass killing and a protagonist biting off his own tongue (or don't) and consider why Hieronimo wrote a play in which each character speaks a different language. What does all this scripted misunderstanding have to do with madness?

People go crazy in The Spanish Tragedy when they can't get what they want: whether they want revenge, an out of reach girlfriend, or just to be heard, madness is the only effective way to get what you want in a corrupt system that denies fundamental human emotions.

It's not him, it's the system that's crazy. Hieronimo is a moral man who discards his values and even his sanity because it takes a nut to survive in a crazy world.

Bel-Imperia is the only avenger in the play that doesn't go crazy, but her suicide serves as a reminder that female assertiveness in the play is only possible through self-sacrifice.