One of the nine BPD symptom areas · Updated November 12, 2026
Unstable Relationships and Splitting in BPD Explained
DSM-5-TR describes a pattern of unstable and intense relationships that alternate between extremes of idealisation and devaluation. This shift is often called splitting: a person is experienced as all good or all bad, with little in between.
What it can feel like
Closeness can feel wonderful and then suddenly unsafe. Someone who seemed to understand you completely can, after one hurt, seem careless or cruel. Both views feel entirely true in the moment, which makes relationships confusing for you and for the other person.
How it differs from everyday experience
Every close relationship has disappointment in it. In this pattern, one hurt can overturn the whole picture of a person, and the earlier warm view becomes hard to remember until the feeling passes. The swings are tiring for both people and are not chosen.
What is often underneath
When a feeling is very strong it tends to colour everything about a person, so the memory of their good side becomes hard to reach. Holding both, that someone can care about you and also disappoint you, is a skill that can be learned and practised.
Where else this experience shows up
Stormy relationships can also follow trauma, occur in a relationship that is itself unsafe, or accompany mood episodes and substance use. Context matters before any conclusion is drawn.
One symptom area on its own never establishes borderline personality disorder. A diagnosis considers a long-standing pattern across several areas, its effect on daily life and other possible explanations, and it can only be made by a qualified professional.
Something to try: Hold both sides
Use this when your view of someone has just flipped.
- Finish this sentence about them: "Right now I feel ___ because ___."
- Add a second sentence that is also true: "And last week they ___."
- Postpone any decision about the relationship for 24 hours. If something needs saying, describe the one event and ask for one specific change.
How to raise it with a professional
You could say something like:
“My relationships swing between very close and very painful. Is there a therapy that works on this directly?”
See how this area fits with the other eight
The free in-depth test shows how often you recognise each of the nine areas and gives you a summary to share. No account or email.
The other symptom areas
Sources
- National Institute of Mental Health: Borderline Personality Disorder
- NICE guideline CG78: Borderline personality disorder: recognition and management
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), 2022. Criteria are paraphrased here.
This page is educational and does not replace an assessment by a professional. How our content and tests are made · Written by Tyr, founder and editor