My Wife Has Been Using Diphenhydramine As A Sleep Aid

my wife has been using diphenhydramine as a sleep aid for over 5 years, no longer smokes but hits the vapor pipe with nicotine every chance she gets. also she drinks at least 32 oz of coffee a day. she has become irritable and very over reactionary. i will come in to the bedroom and she will often scream as if she was about to be attacked, when i roll over in bed she wakes up and says that she needs her sleep as if she has not been able to sleep all night, then goes right back to sleep. i know that the coffee, nicotine & diphenhydramine is playing a big roll in her behavior and i have tried to talk to her about this but she will have no part of this conversation. can you offer any studies or literature that can help her be convinced that these things are majorly affecting her behavior. Please help, Thank you very much.