First Person Plural
Dissociative identity disorders association

Complex Dissociative Disorders

When any one or more of the five types of dissociative experiences – depersonalisation, derealisation, amnesia, identity confusion, identity alteration – occur as continuing and/or repeated episodes, i.e. becomes chronic, you may meet diagnostic criteria for a dissociative disorder.  Strictly speaking, for a dissociative disorder to be diagnosed, episodes of dissociation must be interfering with your work, social, home, family or student life and for many people this is the case. However, some people who are actually very distressed by repeated dissociative episodes, hide this extremely well – (indeed some aspects of dissociation help them to do this) – and they appear highly functional.

There are several dissociative disorders, including Depersonalisation/Derealisation Disorder, Dissociative Amnesia (with or without Fugue), Dissociative Disorder Not Otherwise Specified (DDNOS), Other Specified Dissociative Disorders (OSDD), Dissociative Identity Disorder (DID) aka Multiple Personality Disorder (MPD) and the dissociative (conversion) disorders of sensation or movement.  There are also many other mental health or psychological conditions which are not classed as dissociative disorders but nonetheless have significant dissociative features.  Notably, these include complex post-traumatic stress disorder and borderline personality disorder, However, First Person Plural’s primary focus is on the two most complex of dissociative disorders namely Dissociative Identity Disorder (DID) / Multiple Personality Disorder (MPD) and the DID-like Type 1 Dissociative Disorder Not Otherwise Specified (DDNOS) and Other Specified Dissociative Disorder (OSDD).

Dissociative Identity Disorder / Multiple Personality Disorder


These are two names for the same condition and despite the phrase ‘personality disorder’ appearing in one of the names it is not and never has been classified as a personality disorder.  First Person Plural’s preferred term is Dissociative Identity Disorder (DID) as this is the more up-to-date and accurate descriptor.

DID is the most complex of the dissociative disorders.  It involves all five of the types of dissociation outlined above, often also symptoms which fall into the conversion type of dissociation, and commonly a range of non-dissociative symptoms.   Identity Alteration and Amnesia are usually severe, with Depersonalisation and Derealisation also being present at a moderate to severe level, episodes of Identity Confusion also occur.

Dissociative Disorder Not Otherwise Specified (Type 1) / Other Specified Dissociative Disorders (Type 1)


The other type of complex dissociative disorder which First Person Plural focuses on is known as Type 1 Dissociative Disorder Not Otherwise Specified (DDNOS) or Type 1 Other Specified Dissociative Disorder (OSDD).  There are other types of DDNOS or OSDD but Type 1 is DID-like and all references to DDNOS or OSDD on this website refer only to Type 1, unless indicated otherwise.

People with DDNOS almost meet diagnostic criteria for DID except that their experience of being multiple selves has not or cannot be observed by others and/or they do not have severe amnesia.   In 2013, a new fifth edition of the Diagnostic and Statistical Manual (DSMv) was published.  This removed the DDNOS label and changed some diagnostic criteria for DID.  Both DSMiv and DSMv terminology remain in common usage. People whose experience of being multiple selves is subjective or has not yet been seen by others, and they have severe amnesia would, using DSMiv, be diagnosed with DDNOS, but, using DSMv, they meet the revised criteria for DID. Those whose experience of multiple selves is either subjective or objective but they do not have severe amnesia for the present or recent past would, in DSMiv, be DDNOS, and in DSMv they would be considered OSDD.

People who have DDNOS/OSDD usually experience several of the five types of dissociation described above.  These may be at a less severe or less frequent level than those who have DID but DDNOS/OSDD are complex dissociative disorders, which can be as difficult to live with as DID.  As with DID, there can be a myriad of both conversion type dissociative symptoms and co-existing non-dissociative problems.