Dear Amy: My 14-year-old daughter, "Carrie," has been in both inpatient and outpatient care for years for mood disorders, anxiety, depression and self-harm.

She also struggles with a binge-eating disorder and has become quite overweight. She is under the care of a pediatrician, pediatric psychiatrist and therapist. She is getting great care, but treating an eating disorder associated with mental-health issues is extremely challenging.

My mother is a major stressor. She takes every opportunity she can to talk to me about my daughter's weight, how it negatively affects her life, ruins her health, etc. She also constantly asks me what I'm "going to do about it" and when I will "get her into a program."

My mother's obsession with my daughter's weight has become so overwhelming that I try not to be alone with her or talk too long on the phone with her.

I have explained to my mother time and again that I take advice from experts who are managing her care, but that doesn't seem to matter to her.

My mother also shares her negative viewpoints about my daughter's makeup, hair and clothing choices.

I know she cares about Carrie, but I really need to set some boundaries. I am genuinely starting to dislike my mother. She is extremely invasive and is wearing me down.

I wish she would talk to a therapist about this instead of me. What would you advise?

Amy says: You say that you have repeatedly explained the course you are following regarding your daughter's health.

You don't say that you have told your mother that you won't discuss this with her at all.

Building a boundary is sometimes like putting up a picket fence — you install it, slat by slat. And sometimes, building a boundary is like lowering a garage door: You say what you are going to do, and then you do it. And then you keep doing it — calmly — until the person catches on. In your case, you would be trying to retrain your mother away from what you claim is her "obsession" with your daughter's weight.

Be aware that if you really lowered the boom, you wouldn't be able to vent to your mother or use her as a sounding board. This requires discipline on your part.

Explain: "I cannot handle your constant negative reaction. You have the right to your opinion, but I need you to keep it to yourself because honestly, what I need right now is love, support and positivity. I'm not getting that from you, so I'm going to stop discussing Carrie's situation with you."

When your mother asks how Carrie is doing, say, "She's hanging in there," and change the subject. When she offers an unsolicited negative assessment, say, "Nope, Mom, remember? I'm not going there."

Send questions to Amy Dickinson at askamy@amydickinson.com.