Mitch discovers Rose has been keeping a huge secret from him. She suffers from Bipolar disorder, a manic depressive condition which she has been managing with a Lithium dosage. However since discovering her pregnancy, she has discontinued the medication, leaving herself vulnerable to manic mood swings. The fact Rose kept this from Mitch underlines her insecurity in the relationship. Even Mitch does not realise how much this insecurity is focussed on his friendship with Terri.
