The ODDS of OSDD Diagnosis: The Most Commonly Underdiagnosed Dissociative Disorder
Dear Community,
Today we are proud to present this article about the ODDS of OSDD diagnosis researched and written by The Plural Association team in collaboration with the Plural community.
This article comes with cross-links to two other articles we have written that connect directly to this topic. We strongly suggest reading our article on OSDD-1A and OSDD-1B first if you have not already, as it lays important groundwork for understanding what OSDD is and where some of the misinformation around it comes from. We also link to our Plural Spectrum Tool article later in this piece.
We are writing this article because OSDD has been systematically overlooked: by clinicians, by researchers, and by culture. The data shows this clearly. This article is not about challenging your identity or your diagnosis. It is about naming a systemic failure and showing, with evidence, that OSDD is not what it has been treated as.
Who This Article Is For
Before we begin, we want to be clear about who we are writing this for, because this article is not only for people with an OSDD diagnosis.
The Plural Association defines Plurality in our legal documentation as anyone who self-identifies as having or being more than one individual within a single body, no matter the words they use to describe that experience. That definition is intentional. It is wide. It includes people with a DID or OSDD diagnosis. It includes people who identify simply as Plural, as a system, as multiple, or with any other label that fits their experience. It includes people who have never sought a diagnosis and never intend to. It includes people who do not experience their Plurality as a disorder at all.
This article focuses on OSDD specifically because OSDD systems have been particularly let down by clinical and cultural systems that should have served them better. But the broader failure we are describing, the failure to take Plural experience seriously in all its forms, affects the entire community.
What Is The Difference Between OSDD and DID: A Brief Orientation
Both OSDD and DID are dissociative disorders. Both are real. Both cause clinically significant distress and impairment in daily life. Neither is more valid than the other.
The core clinical difference between DID and OSDD comes down primarily to dissociative amnesia. DID includes clinically significant amnesia as a diagnostic criterion. OSDD does not require it. But this distinction is less clear-cut than it sounds: what counts as amnesia beyond ordinary forgetting is inherently subjective, and ordinary forgetting looks very different depending on a person’s age, history, and circumstances. The line between the two diagnoses is not as firm as the DSM implies, and OSDD is not a diagnosis you receive because you fell short of DID. It is its own distinct diagnosis describing its own distinct presentation.
One distinction we want to address directly, because we see it causes confusion in our community: the difference between OSDD and DID is not simply about whether a system experiences their headmates as parts of one person or as distinct people. Some systems experience their headmates as distinct people. Some experience them as parts of one person. Some experience both, or neither, or something else entirely. This is true across DID, OSDD, and all forms of Plurality.
It is also worth naming clearly: not every Plural system has a diagnosis, wants one, or needs one. Plurality is a wide umbrella. Some Plurals live entirely outside of any clinical framework and that is completely valid. How many people with an OSDD diagnosis are Plural? How many Plurals share experiences that might look like OSDD on paper? We do not know, and it does not need to matter for your identity or your experience to be real and valid.
If you want to explore the clinical differences between OSDD and DID in more depth, you can read this article here.
What we will focus on in this article is something that does not get talked about nearly enough: the odds. Because when you look at the research, the numbers tell a very different story than the one our community has been handed.
A note on Non-Plural OSDD:
OSDD is a diagnosis of exclusion (it “does not meet the full criteria for any of the disorders in the dissociative disorders diagnostic class” – DSM-5). Unlike most disorders in the DSM-5, it does not have its own detailed explanation text or diagnostic features section.
There is also significant community confusion around outdated terms like OSDD-1A and OSDD-1B, which are not in the DSM-5 and cannot be diagnosed.
Assuming that dissociation is a natural human experience, that happens at all sorts of intensities and during all sorts of activities, it is possible that not all (pathologized) forms of dissociation lead to Plurality-Multiplicity. Plurality as an umbrella is a community label, not a clinical one. It can only be self-identified with. No one can give it to someone or take it from them. As Plurals, as allies, as helpers, it is important to listen to the person in front of you, and to believe and validate their internal experience(s).
Having an OSDD or DID (diagnosis) does not automatically mean someone is Plural, unless they choose to describe and label their experience that way. It is always up to the person(s) to find the labels that best fit their lived experience. Having OSDD or dissociating a lot does not always indicate someone is Plural.
At The Plural Association, we write about OSDD from a Plural perspective, because that is the community we serve.
What Our Plural Census Says
At The Plural Association we do not let our census data sit in a folder. We use it, because it belongs to the community that created it.
In our 2025 community census, we asked: “Are you alters, parts or self-states of the same one person?” Of the 831 people who answered, 26.7% said yes. That means nearly three quarters of respondents do not experience their headmates that way at all, and that is across the whole Plural community, not tied to any one diagnosis or label.
We then asked respondents how they describe who is in their system. The answers were as varied as the community itself: people, headmates, selves, individuals, insiders, inside family members, entities, introjects, and more. The most common answer was people, followed closely by headmates. This matters, because language reflects experience, and the language our community actually uses tells a very different story than the language clinical frameworks have historically used to describe us.
This connects directly to something we have written about before: personhood. The medical model, as reflected in both the DSM-5 and the ISSTD treatment guidelines, does not easily accommodate the idea that a system may consist of multiple persons. But our census data shows that this is exactly how the majority of our community experiences itself. You can read more about personhood and what it means under the Plural umbrella in our article here.
The Systemic Problem
Over the six years that The Plural Association has been building and supporting our community, we have observed a consistent pattern. OSDD gets treated as a footnote to DID. In clinical spaces, in research, in media, and sometimes even within plural communities themselves: DID dominates the conversation while OSDD sits quietly at the edges.
And Plurality as a non-pathological experience? It is almost entirely absent from clinical literature and mainstream culture alike. The idea that someone might be Plural, might experience life as more than one individual within a single body, and might not need or want a clinical diagnosis to validate that: this is not something the medical world has been willing to engage with seriously. That invisibility has real consequences. It means less research, less clinical training, less cultural understanding, and less access to support for everyone in this community, whether they carry a diagnosis or not.
We want to be clear: this is not the fault of OSDD systems, DID systems, or Plurals of any kind. This is a systemic failure. And the data shows it.
What The Research Actually Says
Research of a not yet peer reviewed meta-analysis of 98 studies, most of which are peer reviewed themselves, revealed that among 31,000 college students, DID had a prevalence of 3.7% while OSDD showed a prevalence of 4.5% (Kate et al., 2019).
Read that again. OSDD is more common than DID.
This makes sense when you think about it simply. Trauma exists on a spectrum. The more severe and prolonged the trauma, and the earlier it begins, the more likely a person is to develop more complex dissociative responses. Most people who experience trauma do not experience the most severe end of that spectrum. More trauma leads to more dissociation, and since most people sit toward the less severe end of the trauma spectrum rather than the most severe end, it follows statistically that OSDD presentations should be more common than DID presentations. And they are. The research confirms this.
And this is only the research that exists. It only captures people who sought diagnosis within a clinical system that already struggles to recognise dissociative disorders at all. It tells us nothing about the many Plurals who live outside that system entirely, by choice, by circumstance, or because the clinical world never offered them anything useful to begin with. The real prevalence of Plural experience in all its forms is almost certainly far wider than any study has yet measured.
Yet the clinical and academic world has not responded to even what the research already shows.
The Research Gap
In 2026, a Google Scholar search for OSDD returns approximately 61,600 results. A search for DID returns approximately 112,000 results.
OSDD is the more prevalent condition. It receives roughly half the academic attention.
We want to be transparent: Google Scholar is not a perfect measurement tool. DID has older terminology, more search term variation, and a longer history in the literature. But the gap is too large to explain away. Half the research means less clinical training. Less clinical training means less diagnostic awareness. Less diagnostic awareness means OSDD systems waiting longer for answers, or never receiving them at all.
And for Plurals who fall outside the diagnostic framework entirely, the research gap is not half. It is almost total. Non-pathological Plurality is barely present in academic literature at all. The community has largely had to build its own knowledge, its own language, and its own support structures. That is part of why organisations like The Plural Association exist.
![‘’We mask [our Plurality] to fit in, we take the mask off to find belonging.’’ The Stronghold System](https://25f43012.delivery.rocketcdn.me/wp-content/uploads/2021/12/there-is-beauty-in-the-struggle.-we-are-in-this-together.-1024x1024.png)
Why DID Dominates The Conversation
DID has cultural visibility. It has films, documentaries, viral social media content, and a name that people outside the community recognise. OSDD has almost none of this. Non-pathological Plurality has even less.
It is already known that it takes on average 6 to 12 years to receive a correct DID diagnosis, even while already receiving mental health care. If DID, the more culturally visible and more researched of the two diagnoses, takes that long, we have to ask honestly: how long are OSDD systems waiting? How many are never correctly identified at all? And how many Plurals have passed through the mental health system entirely without anyone recognising or respecting their experience in any form?
Clinicians who do not receive adequate training on DID are even less likely to recognise OSDD. The vacuum left by this clinical neglect has been filled by non-clinical sources, and as we explored in our OSDD-1A and 1B article, not always accurately. We invite you to read that article for the full picture on where that misinformation came from and why it spread so widely.
What We See In Our Own TPA Community
The Plural Association currently has 600 community members. Choosing a label within our community is entirely optional, and many members may have decided not to label at all, which is completely within their rights and consistent with our definition of Plurality as something that belongs to the person experiencing it, not to a diagnostic manual.
Of those members who did choose to share a label: 59 identified as OSDD systems, 157 as DID systems, and 185 under the broader Plurality umbrella.
The 185 members who identify as Plural are not a gap in the data. They are not undiagnosed OSDD systems waiting to be categorised. They are Plural. Their experience is real and valid exactly as they have named it. And their presence in our community, as the largest single group, reflects something important: many people find that the Plural label describes their experience more honestly and more completely than any clinical diagnosis currently available.
The underrepresentation of OSDD relative to what prevalence research would predict reflects the same systemic pattern we have described throughout this article. Not enough diagnosis. Not enough recognition. And a clinical framework that has never fully served this community in any of its forms.
OSDD Is Not A Straight Line From DID
We want to take a moment here to talk about what the relationship between OSDD, DID, and Plurality actually looks like, because it is not a ladder, and it is not a straight line.
Plurality is not a hierarchy. It is multidimensional. OSDD does not sit below DID. It sits somewhere else entirely. And non-pathological Plural experience does not sit below either of them. The Plural Spectrum Tool, which you can download for free here, illustrates this beautifully. Plural systems vary across many different dimensions: memory sharing, co-consciousness, system stability, internal communication, and more. No two systems are the same. No position on that spectrum is more valid than another.
There are as many ways to be Plural as there are Plurals. This is as true for OSDD systems as it is for DID systems, as it is for Plurals who carry no diagnosis at all.
When The Diagnosis Changes But You Don’t
There is something unique about DID and OSDD that we do not see in most other diagnoses. Imagine healing from bipolar disorder and being rediagnosed as having depression simply because some symptoms had reduced. It does not typically work that way in mental health. But with DID and OSDD, it is technically possible, and it has happened.
As someone who was inpatient at a clinic during the transition from DDNOS to OSDD in the DSM, I witnessed this firsthand. The clinic retested and rediagnosed everyone who wanted to participate. Some people who had been diagnosed with DID received an OSDD diagnosis instead. The circumstances were specific and it was not common, but it happened. Not because they had gotten worse. In some cases, because they had healed. Because the amnesia that had once been present was no longer as prominent.
This is rare. But the fact that it is even possible says something important. If healing from DID can technically move someone into OSDD territory, then these cannot be two fundamentally separate categories with one sitting above the other. They are part of the same human experience of Plurality, expressed differently, at different times, in different people, under different circumstances.
And what happens when someone heals further still, when their Plurality no longer causes them distress or impairment, when it simply becomes part of how they live? The clinical framework has no good answer for that. But the Plural community does. You are still Plural. You are still valid. The diagnosis was always a description of your experience at a particular moment. It was never the whole of who you are.
What This Means For OSDD Systems
Your diagnosis is not a consolation prize. It is not a stepping stone toward something else. It is not almost-DID or not-quite-DID.
OSDD is the more statistically common dissociative disorder presentation. The clinical world has not caught up to what the research already shows, but that is the clinical world’s failure, not yours.
The odds of the OSDD diagnosis were never in your favour. They should have been. That is why we wrote this and our other articles. If you are an OSDD System, please let your Voices be heard in the annual Census, and this invite of course extends to all Systems, no matter the labels you use to describe your unique and individual experience(s).
Closing
This was not the first time the diagnostic framework shifted beneath people’s feet. Before DID there was MPD, Multiple Personality Disorder. Before OSDD there was DDNOS. The labels changed. The diagnostic criteria changed. The people did not. You can read about that terminology history in our article; How they took the Multiple out of Multiplicity – Understanding the history of Dissociative Identity Disorder (DID) Terminology
The DSM will likely change again. It always does. And when it does, some people will find their diagnosis shifts, not because their experience changed, but because the clinical world updated its framework again.
This is precisely why so many Plurals choose to use the Plural label. Not because clinical diagnoses are wrong or unimportant. For many systems, an OSDD or DID diagnosis is life changing and provides access to the support and care they deserve. But because the Plural label offers something the clinical framework never has: stability. Self-determination. A way of naming your experience that belongs to you, not to whichever edition of the DSM happens to be current.
References
Kate, M., Hopwood, T., and Jamieson, G. (2019) The Prevalence of Dissociative Disorders and dissociative experiences in college populations: a meta-analysis of 98 studies. Journal of Trauma and Dissociation. 4(29)
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596
As always, we encourage you and your System to follow your own truth, to soul search, to find words, labels, visions, theories and communities that aren’t only within your values but also match your lived experience and/or long term goals, so that you might find belonging and don’t have to try to fit in.
Thank you for investing the time to read this article. Please, feel free to leave comments or feedback in the comment section.
The Plural Association is the first and only grassroots, volunteer and peer-led nonprofit empowering Plurals. Our works, including resources like this, are only possible because of support from Plurals and our allies.
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About the authors
The Stronghold System are the proud volunteer founders & CEO of The Plural Association Nonprofit. They are from the Netherlands and reside in a 30-something-year-old body, are nonbinary, parents of an amazing child & 3 cats. They got diagnosed with Dissociative Identity Disorder over 10 years ago & also self ID as Plural.