BPDFamily.com

There is a symptom of Alzheimer's called Sundowning. Basically the patient's behavior gets worse when the sun goes down and it gets dark. They get more afraid and tend to lash out.

I swear my sister has this symptom with her BPD. She lives with my mother and goes into mom's bedroom every night to pick an argument and get enraged and just freak out!

I also get most of my nasty texts from her at night.

We swear it's Sundowning but for BPD. Maybe the night affects her more and the fear of being alone is exacerbated?

Anyone else experience this?

Not sure about BPD, but my MIL had the Alzheimer's version of it.  She didn't become enraged or anything.  Her Alzheimer's was just worse at night and she would be more confused about things.

Many people here talk about late night fights and arguments started by their pwBPD.  Check out this thread: https://bpdfamily.com/message_board/index.php?topic=230373.0

I wouldn't necessarily call what your sister does sundowning, but it makes sense that an increase in BPD behaviors at night would be related to abandonment issues. 

How old is your mother,  and is she safe from your sister's dysregulation?

Hi Broken1969:
BPD doesn't stand alone and generally when people with BPD successfully manage their various mental disorders, they can tame their BPD behaviors. People with BPD or BPD traits usually have multiple mental disorders.  Anxiety and depression (as well as more complex disorders), are generally in play.

Anxiety can become more pronounced at certain times of day.  Some people might feel anxious when they first wake up, others might have a greater intensity of anxiousness in the evening.  If someone isn't managing their anxiety successfully, then anxiety builds up - hence her behavior in the evening.  Also, if she has trouble sleeping, some evening anxiety might relate to that.

Is your sister currently being treated for any mental disorder (or has she in the past)?