Please provide an in-depth character summary of Don John from Much Ado About Nothing.I am Don John's psychiatrist and am writing notes about him in...

Well, first, if your question is meant to imply that
Shakespeare wrote in something other than Modern English, you would be incorrect! 
Shakespeare wrote in 100% Modern English.  He just happened to use some words that have
gone out of fashion and often used his words in a very stylized form -- blank verse.  He
also, by the way, made up thousands of words that we use commonly every day -- words
like eyeball and lonely.

But I digress.  To your question
regarding an "in-depth" look at Don John.  Well, unfortunately, Don John, as written by
Shakespeare, is pretty inscrutable.  Here are a few of the most telling things he says
about himself:

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I cannot hide what I am:  I must be sad when I
have cause...eat when I have stomach...sleep when I am drowsy...laugh when I am
merry.

And maybe most
importantly:

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[I]t must not be denied but I am a plain dealing
villain....[L]et me be that I am and seek not to alter
me.

He does say he has a
grudge against Claudio, but much like Iago in Othello, it is hard
to see how that motivation is more compelling than the fact that he is simply a
villain.  It is certainly true that, also like Iago, he is willing to go to great
lengths to ruin the lives of others.  He says, "Only to despite them I will endeavor
anything."

And that's basically the last we hear from him
in the play.  His henchmen, Conrad and Borachio, actually figure more prominently in the
action of the play as they attempt to carry out his devious scheme.  At the end of the
play, it is reported that he has fled.  No redemption or punishment for Don
John.

So, for your assignment, you'll need to take the
things that he says about himself and create your own psychoanalysis.  Good
luck!