Depression and eating disorder in 13 year old stepdaughter

Hi y'all. I got a disturbing text from SD13 today saying she's depressed and indicating that she has an eating disorder.

A bit of background first and no offence is intended to anyone:

Her 19 year old brother suffers from chronic depression and bulimia - this was withheld from the father (my partner). He was sent to a private inpatient clinic to manage the eating disorder and try to get on top of the depression but didn't like the structure so didn't continue with the treatment.

There is a history of mental illness (depression, bipolar disorder, borderline personality disorder) on the maternal side of her family. SD13 is prone to exaggeration and tells tall stories and outright lies quite often and gets caught out. She has frequent conflict with friends and I wonder if she's getting bullied a bit at school but she is very closed.

The message I received this morning was:

"I've been feeling really really depressed lately. When I feel really depressed I'll starve myself and won't eat for a few hours and I can't control it anymore and I have been losing weight too fast."

I honestly don't know what to make of this. Apparently her mother "wants her to see someone" but hasn't made an appointment. She says the "depression" only comes about when she goes home from school. I wonder if it's an attention seeking thing as she has said she feels lonely at her mother's house. She has to share the house with the mother, mother's boyfriend, 19 year old brother, her 24 year old sister and her husband and their 2 year old toddler.

Any thoughts or ideas?

Even if it is "only" attention seeking, she needs help for her mental state. Attention seeking in a teen can swiftly escalate.

I had an eating disorder and depression as a teen, so don't rule it out entirely.

I refuse to rule it out but I don't know if the mother is taking this seriously. I'm very concerned about her.

What was your experience Ca Plane Pour Moi?

I was given no help, despite asking for it. Over 20 years after first asking for help, and about a decade after seeking help, I still suffer.

This is the thing that concerns me. The mother still hasn't made an appointment. SD told me this morning that their usual doctor is fully booked this week. No mention of an appointment being made for next week. I have made an appointment for SD to see our doctor this Saturday. I have a sinking feeling that SD will say she doesn't feel like seeing a doctor or use some excuse to get out of it. I hate feeling like that about her.