You have to help her with her drinking problem. When you go to the kitchen, you sometimes find her with a glass of wine. You have to talk to her and convince her to stop.
I believe Anna starts to get drunk not long after you start Adrian Anna Sharing Route.
1st Encounter: "Is Everything Alright?" > "Are you sure everything is alright?" > "Have I done something wrong?"
2nd Encounter: "Is Everything Alright?" > "Are you sure everything is alright?" > "It was never about Dad, it is about us"
3rd Encounter: "Is Everything Alright?" > "Are you sure everything is alright?" > "Because you're my .... and I love you"
Then the next time you meet her in the kitchen, she'll apologize and promise not to drink ever again ( Savior Trophy Unlocked ). Then you can have fun with her in the Master Bedroom.