Surgery and ADD

My partner has ADD and depression/anxiety.  She's having major surgery next week.  When she had minor surgery a few months ago her depression seemed to heighten for a few weeks.  I'm concerned it will be worse this time around because she will be under more anesthesia for a longer period of time.  Has anyone else noticed this when their partner has surgery?  Does anyone have any ideas about how to minimize an uptick in post-surgical ADD/depression symptoms?  Thank you.