From trauma to “multiple personalities”: Twenty “secrets” of dissociative identity disorder (DID)- Part 1


Received: November 2022

【Authors/ 作者】

Andy H.W. Fung, PhD, RSW (Social worker and researcher from Hong Kong) (

Cindy C.Y. Leung, MSS, RCP (Clinical psychologist from Hong Kong) (

Elly C.Y. Lee, MD(Psychiatrist from Taiwan) (

【中文概要】「多重人格」或「人格分裂」是大家都聽過的心理障礙,不時出現在電影情節裡。然而,大家對這個現已改名為「解離性身份障礙」(DID)的精神科診斷,了解又有多少?本文由學者和精神科醫生,為大家整理並回答20個關於DID的常見問題,附以科學文獻供參考。本文亦獲「國際創傷與解離學會」(ISSTD)前理事長Dr. Colin A. Ross, M.D.支持和給予寶貴意見。原來,DID這個充滿戲劇性的現象,離我們可能不遠。原來,多重人格有可能是孩子面對長期痛苦時的倖存方法。當我們都疼惜孩子、好好保護孩子,原來就有可能預防DID。


The authors would like to thank Dr. Colin A. Ross, M.D. (a past President of the International Society for the Study of Trauma and Dissociation) for his support and comments in this article.

“Multiple personalities” is a term that often appears in movies, dramas, novels, newspapers, and online forums. You may have heard of “Monsters Inside: The 24 Faces of Billy Milligan”, “Kill Me Heal Me”, and most recently “Split”, but many people don’t really understand what “multiple personalities” is. What is it?

The story of “multiple personalities” in the clinic

Mei grew up in a strict Chinese family environment where her parents often had high expectations of her and they valued family prestige (“face”), so she was always afraid to express her emotions at home. Mei was 30 years old and had a successful career, but she was always troubled by insomnia and mood problems, and she had been diagnosed with depression.

Once, an elder colleague in the company approached Mei and talked to her, and she suddenly felt very frightened and cowered under the table, mumbling, “I’m sorry, Uncle! Don’t hit me! I’m sorry!” Afterwards, she had nightmares and visual images from time to time of her childhood experiences of being beaten by older people.

Recently, Mei told her psychiatrist that she often found herself with a lot of new clothes and toys at home, but had no recollection of where they came from; they were all in styles she would not normally wear, and she had not played with toys for many years. Moreover, she was upset as she often heard a child’s voice in her head telling her to run into the car in front of her on the commute to work (which might result in her killing herself!). She also complained that she heard voices making comments inside her head while she was on the phone with a client for business-related issues, making it hard for her to hear what her client said. These voices often appeared and “took over” her body, causing her to “lose consciousness”. When she “woke up,” she suddenly found herself in a nightclub, wearing strange clothes without knowing what had happened and how she had ended up in the nightclub wearing such clothes.

After an in-depth assessment, the psychiatrist told Mei that she was suffering from “dissociative identity disorder.”

About “multiple personalities” – 20 secrets you should know

Mei’s story is actually not uncommon in reality. She had a wide range of emotional and behavioral problems, and medication was not working well for her. She had sudden “flashbacks” of her painful childhood memories, which is a common dissociative symptom for trauma survivors. She found things that didn’t belong to her, lost her memory of current events, heard voices inside her head, etc. – These symptoms are all common clinical manifestations of dissociative identity disorder (DID).

Is it possible that “multiple personalities” or DID is not just a fiction, limited to movies and novels? Is it possible that people around us may be suffering from this mental health condition? If so, is it possible to recover from “multiple personalities”?

This article provides answers to some common questions about DID. Perhaps, after you have learned more about “multiple personalities”, you will have an increased understanding of those suffering from this condition in our society – and you will recognize the importance of protecting our children in the community!

1. What is “dissociation”? What does this have to do with “multiple personalities” or DID?

“Dissociation” means that there is a disturbance or difficulty in the process of integrating our biopsychosocial experiences (e.g., emotions, physical activities, memories, identities) [1, 2].

Some dissociative experiences can be normal in our daily lives, such as daydreaming and general forgetfulness, for example, when a person is daydreaming and cannot hear others talking to him or her.

Dissociation is sometimes a natural response to trauma and stress. For example, a person under stress may feel numb for a while. When a person is too focused on work, he or she may not feel hungry even though he or she is physically hungry. A person who is frightened may not be able to immediately verbally recall what has just happened. 

However, some dissociative experiences may be clinically significant, thus requiring professional assessment.

For example: a childhood abuse survivor could feel like he or she is not the one being abused; or a family violence victim keeps having flashbacks of dissociated painful memories, and the trauma-related scenes also frequently come back as nightmares.

Dissociative symptoms have been found to be quite common in people with trauma-related disorders (such as post-traumatic stress disorder (PTSD), acute stress disorder (ASD), borderline personality disorder (BPD), and the dissociative disorders).

Previously called multiple personality disorder (MPD), or split personality, the condition is now known as Dissociative Identity Disorder (DID), which is a mental health disorder involving severe pathological dissociation in terms of memories and identities; in other words, the main characteristic of DID is severe pathological dissociation, although pathological dissociation may also occur in non-DID individuals.

2. Does DID exist in reality?

DID is a psychiatric diagnosis officially recognized by international diagnostic manuals, including DSM-5 [1] and ICD-11 [3]. In the DSM system, DID is classified as a type of dissociative disorder. Prior to 1994, DID was referred to as multiple personality disorder in the DSM. Moreover, DID has been shown to be a reliable and valid diagnosis according to scientific research [4, 5]. Therefore, it is certainly “a real diagnosis”.

3. Is DID the same as “schizophrenia”?

DID and schizophrenia are two different psychiatric diagnoses. Although there are some similarities or commonalities, there are some differences between the two. The key symptoms of DID are “dissociative amnesia” and “identity alteration,” which are not the primary symptoms of schizophrenia. It is important to note that both DID and schizophrenia patients are likely to experience “hallucinations”, especially hearing voices [2, 6].

4. Is DID very rare?

There have been many epidemiological studies on DID in the last 30 years. Reviewing reports from various regions and cultures, scholars suggest that the prevalence of DID in the general population is about 1% – 3% and that DID affect about 4% of psychiatric inpatients [7, 8]. In the largest meta-analysis of studies on the prevalence of dissociative disorders (DDs) [9], dissociative disorders were found to affect 11.4% of college students, and the prevalence of DID was found to be 3.7%. However, unfortunately, patients with DID are often labeled as having other psychiatric disorders, while the DID remains unrecognized [7, 10].

5. Why is DID hard to identify?

There are many reasons that may explain why DID is often unrecognized in the health and social care service systems. First, because of their painful life experiences, many trauma survivors with DID find it difficult to trust others – they will probably not disclose their inner experiences easily unless the therapist makes them feel safe. Second, as will be further discussed, some people with DID are not aware of their alters; even though they recognize their own strange experiences, they may not know what has happened or why. Third, since people with DID are often complex trauma survivors, they often have many other presenting problems (known as comorbid symptoms), such as depression, anxiety, substance abuse, and hearing voices – these comorbid symptoms can result in a diagnostic challenge. Fourth, there is a lack of training in the assessment and treatment of trauma and dissociation in many mental health professional curricula, and therefore some practitioners may not have enough understanding of trauma, dissociation or DID. As a result, when the client presents with dissociative symptoms, the practitioner may only focus on what he or she is most familiar with (e.g., depressive symptoms, substance abuse).

6. Is pathological dissociation only found in certain cultures?

The core feature of DID is pathological dissociation. Although some professionals believe that pathological dissociation is unique to North American culture, scholars in the field of trauma and dissociation have found DID in many different cultures. For instance, severe pathological dissociation and DID are found not only in United States and Canada, but also in many other cultures and regions around the world, including Turkey, the Netherlands, Korea, Japan, India, Taiwan and Hong Kong [8, 11-15].

Individuals suffering from DID can be found in literature from Europe in the 16th century [16], and pathological dissociation has been observed in the ancient Chinese medicine literature [17]. All in all, pathological dissociation is clearly a cross-cultural human phenomenon. Moreover, a recent cross-cultural study found that pathological dissociation was particularly associated with childhood betrayal trauma in both Chinese-speaking and English-speaking research participants [18].

7. Do people with DID have more than one personality?

In fact, DID involves dissociation of the personality; in other words, people with DID have only one personality, just like everyone else: Each dissociated “personality” is called an “alternate personality state” or “alternate identity”, even though these “alters” may have different ages, personalities, genders, preferences, memories, and behaviors. All these “alters” add up to a complete personality. That explains why the DSM has renamed multiple personality disorder (MPD) as DID – the person does not have more than one personality; instead, they have considerable dissociation in their identity.

8. Does everyone have multiple personalities?

As mentioned above, everyone has only one personality, but we may have multiple facets of our personalities. We all have dissociative experiences from time to time. It is normal for us to have many different roles in our lives, or to feel some inner conflicts, for example about who we want to become. However, most people don’t hear voices in their heads, come to in strange locations not knowing how they got there (in the absence of drugs or alcohol), find clothing in their closets they don’t remember buying, or get told by friends of behaving very differently from usual without remembering what happened.

9. Do all people with DID have a history of childhood abuse?

In a sample of 296 individuals with DID, 93% reported having experienced childhood physical abuse or childhood sexual abuse [19]. In fact, most people with DID have experienced complex childhood trauma – it does not have to be physical or sexual abuse. Even family violence, verbal violence, emotional neglect, lack of parental love, peer-bullying, medical trauma, poor parenting, etc., may overwhelm one’s ability to process and integrate one’s own experiences – especially during childhood.

10. What does trauma have to do with dissociation?

When a person experiences trauma or considerable stress, if these physical and emotional experiences are too much to bear, they may not be successfully integrated into the person’s personality structure for a while, and this “inability to integrate” means dissociation.

For example, a survivor of a car accident may not be able to bear the overwhelming emotions and painful memories of the event, and therefore she may lose the memory related to the accident. She may experience nightmares and flashbacks after the event. In this example, the survivor may suffer from post-traumatic stress disorder (PTSD), which involves pathological dissociation.

For a child whose personality structure has not been well developed, if he or she has experienced complex trauma (e.g., domestic violence, an invalidating environment), he or she may not be able to process and integrate these experiences. In order to survive, he or she may feel like he or she is not the person being hurt; he or she may be someone else. Especially in the context of betrayal trauma where the abuser is also a caregiver, the child may need to rely on the abusive caregiver to survive – to do so, he or she may need to dissociate the painful memories and emotions (e.g., anger) related to the abusive caregiver. This is the beginning of DID’s self-defense mechanism.

Trauma may overwhelm one’s ability to integrate one’s own experiences, leading to dissociation of the personality. As some scholars have proposed, such dissociation can be involved in ASD, PTSD, complex PTSD, BPD, other dissociative disorders, and severe DID [20]. Many post-traumatic reactions or symptoms are dissociative in nature.

11. There are scales for assessing depression, is there any scale for assessing dissociation?

The first scale to assess dissociation was published in 1986 [21]. There are already many instruments with good psychometric properties (i.e., reliability and validity) to assess dissociative symptoms and disorders, including the Dissociative Experiences Scale (DES), and the Somatoform Dissociation Questionnaire (SDQ).

12. Is it possible for a person with DID to know that he or she has other “alters”?

For an individual with DID, the individual’s alternate personalities may be aware of one another; maybe only one of them is aware of the others; or maybe all of them are unaware of one another; they may have mutual awareness, one-way (asymmetric) amnesia, or two-way (symmetric) amnesia [22]. In addition, when an alter is taking control of the body, other alters (including the host personality state) may or may not be aware of what’s going on. There can be different level of co-consciousness and co-hosting, varying from person to person. Therefore, it is incorrect to say that “a person with DID must not be aware of his or her alters.”

To be continued in Part 2.


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