Other Specified Dissociative Disorders

What Are Other Specified Dissociative Disorders (OSDD)?

OSDD, or Otherwise Specified Dissociative Disorder, is a complex mental health condition that falls under the umbrella of dissociative disorders. Unlike Dissociative Identity Disorder (DID), where distinct personalities, or alters, coexist within an individual, OSDD is characterized by less defined identity disruptions. Although the basic symptoms are similar, there are at least 5 different subtypes of OSDD that are characterized by varying degrees, lengths, or causes of disassociation.

Please note: OSDD and its respective subtypes are currently not well documented, and are currently undergoing changes in symptom identification and classification, including in the DSM-5 Manual. 


OSDD 1a is a subtype of OSDD that is the most similar to DID. “Type 1a,” emphasizes pronounced amnesia as a defining feature. Individuals with this subtype may experience significant memory gaps, impacting daily functioning, but the alters are not always definitively pronounced individuals. People who do not quite meet the DSM-5 criteria for dissociative identity disorder often fall into this category, having at least 2 distinct alternate states, but not always alternate identities or switching between them. 


This subtype, referred to as “Type 1b,” emphasizes identity fragmentation. Individuals in this category may grapple with a more pronounced and distinct sense of identity confusion compared to other OSDD presentations, but lack the day-to day amnesia between alters.


This subtype is generally associated with brainwashing, torture, programming, etc. OSDD-2 includes the type of ‘brainwashing’ or control that can occur in cults, during political imprisonment or during torture. In such cases people may begin to be confused about or question their identity.


This subtype is characterized by severe dissociative symptoms that appear immediately after a traumatic event. This acute state of dissociation usually lasts less than a month, with symptoms lasting from hours to days. Reactions can include depersonalization, small periods of amnesia, and changes in sensory-motor functioning. This type of OSDD can also occur after traumatic brain injuries or seizures, and are treated as temporary state due to a sudden change in brain functionality.


This subtype, “Type 4”  specifically refers to dissociative trances. These trances do not have other causes (other conditions, drug use, spiritual practices, etc), and can be either singular or reoccurring. The symptoms of a dissociative trances are a narrowing of awareness of immediate surroundings or unusually narrow and selective focusing on specific environmental stimuli; and the restriction of movements, postures, and speech that is experienced as being outside of one’s control. The trance state is not characterized by the experience of being replaced by an alternate identity, but can often result in amnesia.

PDID (Partial DID)

Partial dissociative disorder patients experience disruptions of identity similar to DID, PDID being characterized by a ‘dominant’ personality which is usually at the front, functioning in daily life, with any non-dominant personalities only functioning internally, whether cognitively or perceptually. Switches are infrequent, often only happening during particularly emotional or stressful experiences such as moments of extreme stress, moments of self-harm, or related to experiencing memories of a traumatic event.

According to the ISST-D, PDID is a diagnostic term you’ll most likely find used outside of North America.


In the past, DDNOS (Dissociative Disorder not Otherwise Specified) was used as a ‘catchall’ in previous DSM iterations. Today DDNOS is an outdated diagnosis and OSDD is currently used specific diagnoses. This is why if you or a loved one may have had a DDNOS diagnosis you may be confused as to the lack of conversation about that disorder nowadays. It no longer gets diagnosed and if you were to get diagnosed today, you would likely be diagnosed with one of the subtypes of OSDD. 

Personal Experience with OSDD 


There are about 38 or 39 of us. Our system name is our collective name, but that name is also is our main fronter, we took that name because they forfeited their identity to have final say on stalemates.

The name we go by when we mask is different than our system name, and due to us discovering our DID when we were also transitioning gender we discovered that name was actually the name of an alter later on, we eventually had to change their alter name because they were getting called to the front by their name too much.

We’re always in control of the body a lot like daydreaming, just a lot more invested for way longer periods.

Usually I’ll only be partially aware whether someone is out or not, its difficult for me to differentiate sometimes, I know certain lexicon and phrasing can help us understand though, also tone and sound of voice changes a lot for us.

I often don’t know when other alters are around, they poke their heads out and have some fun when they see a need or an opportunity but I never try to force it, it’s like the main fronter is the baseline that the body resets to when no one else wants to be around.

If we have prompting we have an amazing memory for all past events, its just they’re all storyboard mode and I cant process them, then someone takes all 37 years away and I go back to living in the twilight. — AC


International Society for the Study of Trauma and Dissociation. “Fact Sheet IV: What Are the Dissociative Disorders?” ISSTD, 2020, https://www.isst-d.org/wp-content/uploads/2020/03/Fact-Sheet-IV-What-Are-the-Dissociative-Disorders_-1.pdf.

Duncan, Stephanie. “Comparing OSDD-1 and DID.” DID-Research.Org,https://did-research.org/comorbid/dd/osdd_udd/did_osdd

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Hart, O., Nijenhuis, E. R. S., & Steele, K. (2006). The haunted self: Structural dissociation and the treatment of chronic traumatization. New York: W.W. Norton.

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American Psychiatric Association. (2013). Dissociative Disorders. In Diagnostic and statistical manual of mental disorders (5th ed.). http://dx.doi.org/10.1176/appi.books.9780890425596.dsm08

International Classification of Diseases, Eleventh Revision (ICD-11), World Health Organization (WHO) 2019/2021 https://icd.who.int/browse11.

Last updated on February 13, 2024
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