1. Misdiagnosis Rate
Up to 80–90% of people with DID are misdiagnosed before receiving a correct diagnosis.
Source: Brand et al., 2009; ISSTD Guidelines
The average delay in correct DID diagnosis is 6–12 years after entering the mental health system
2. BPD as the Most Common Misdiagnosis
In a review of 20 DID studies (Brand et al., 2014), BPD was the #1 most common misdiagnosis.
Patients with DID are frequently misdiagnosed with BPD, bipolar disorder, or schizophrenia.
Why It Happens: Clinical Overlap & Bias
Symptom Similarities
Clinicians often misinterpret switching or amnesia in DID as mood instability in BPD.
Lack of DID Training
Only 17% of clinicians feel confident in diagnosing DID.
Source: Brand et al., 2016
Most textbooks and psych courses gloss over DID or frame it as "controversial."
Bias Toward Simpler Diagnoses
Many professionals default to BPD because it's better known and "fits" the trauma and the emotional reactivity pattern.
DID is still stigmatized and doubted, despite decades of research backing its existence.
Persecutors Are Misunderstood
Almost every system has one or more persecutor alters who may self-harm, sabotage, or act out destructively. This can look like impulsive BPD behavior, but it’s not coming from the same root.
Key difference:
In DID, the host or other parts might have no memory of what happened, because another alter did it. In BPD, the person remembers and feels the emotional impact of their actions.
But professionals see:
Self-harm
Suicide attempts
Risky behavior
…and go: “Oh, must be BPD”, ignoring signs of dissociative switching or memory gaps.
Core differences between Dissociative Identity Disorder & Borderline Personality Disorder:
psychologically
neurologically
behaviorally
Core Diagnostic Differences
Brain & Trauma Processing Differences
Neurological Imaging
DID brains show compartmentalized activity during identity switches (e.g., Reinders et al.).
BPD brains show hyperreactivity to emotional stimuli but no evidence of distinct neural patterns for different “selves.”
Trauma Type & Onset
DID: Chronic, severe, often early-childhood trauma (before age 7–9); fragmentation develops and remains as a coping strategy.
BPD: Often chronic trauma, neglect, or emotional invalidation during childhood/adolescence; identity becomes unstable, but not divided.
Misdiagnosis Warning Signs
If a client:
Says “I don’t remember doing that” frequently
Refers to themselves in third person or says “part of me wants to die but part doesn’t”
Refers to themselves using plural pronouns
Experiences strange internal dialogues that feel not-their-own
Wants to say something but suddenly changes their mind as if something or someone is stopping them
Has sudden shifts in handwriting, preferences, posture, voice, etc.
That’s not typical BPD.
That’s a red flag for DID or OSDD-1.
Very short summary:
DID:
“I have many parts inside of me, and they don’t all know or agree with each other.”
BPD:
“I don’t know who I am, and I feel like I change based on who I’m with.”
Written by SarcasDID
SarcasDID & Bright
Mental Health Advocates, Founders of mulTIDimensional
IG: sarcasdids & bright.system
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