Dissociative identity disorder (DID) is a mental health condition with strong links to trauma, especially trauma in childhood. Understanding the causes can help you manage this condition.

DID is an often misunderstood mental health condition. While stigma is starting to shift as more people understand the condition and why some develop it, misconceptions still occur.

Dissociative identity disorder was previously called multiple personality disorder, but professionals no longer use this term.

If you believe you or someone you know may have DID, help is available.

One aspect of creating a treatment plan is to figure out and understand the unique causes behind DID for that individual. This helps them work toward healing the trauma that typically underlies the condition.

DID is a type of dissociative disorder.

Some research states that up to 1.5% of community samples had DID, though research is limited due to the condition being so underrecognized. People of all ethnicities and income levels may have it. It occurs in women 9 times more often than in men.

If you have dissociative identity disorder, you have two or more separate personalities or “alters” that control your behavior at different times. The average number of alters is believed to be around 10.

You might not be aware alters exist — but others around you may have noticed them. Shifts between alters are involuntary.

You may notice odd gaps in your memory from when a different alter was in control. In fact, it’s common for people with DID to report amnesia or a loss of time.

Alters can show striking differences. For instance, one alter may speak with a different accent or have a softer way of speaking. They might have different opinions or a different gender identity, and even physical differences — like left- or right-handedness, or the need for a glasses prescription.

People with DID aren’t simply suggestible or taking on social roles. They have physical neurological differences and clear differences in cognitive function that are distinct from individuals who don’t have DID.

DID is usually associated with adverse experiences in someone’s past and traumatic memories.

In fact, the American Psychiatric Association reports that 90% of people with DID have a history of childhood abuse and neglect, based on research from the United States, Canada, and Europe.

Dissociation — a major part of DID — is a defense mechanism the body uses to reduce your awareness during overwhelming trauma.

Dissociation feels like a detachment or the feeling of being outside your own body.

When you dissociate during a traumatic experience, it feels like someone else is having that experience — not you. You might feel like you’re watching the scene from a distance. Thus, dissociating can be a way for you to escape a situation you’re unable to escape.

If you experienced physical, emotional, or sexual abuse in childhood, you may have dissociated as a form of self-defense.

In the case of DID, the traumatic event or events cause the self to fragment into a number of different selves, or alters. Some alters may be holding on to traumatic memories, while others are blocked from accessing these memories.

You may dissociate the memory of the situation, place, or feelings about an overwhelming event. This often makes it difficult to remember the details of the events later.

When someone with DID seeks help, they usually aren’t aware of their condition. This is partly due to memory loss or amnesia that blocks your awareness of other alters.

Researchers have shown that children can learn to dissociate from a very young age. According to NAMI Michigan, the average age for alters to first start appearing is 5.9 years old.

Scientists have found that brains of people with DID are different from those of people without the condition.

Studies have also shown differences in areas of the brain that are associated with the different alters.

In one study from 2014, researchers measured the volume of the brain region involved in memory (the hippocampus) in females diagnosed with DID.

The researchers found that participants had a significantly smaller hippocampus compared with controls. Moreover, those with more severe traumatic experiences in childhood had a smaller hippocampus.

It’s important to note that this study was only in females of Western European ancestry. Scientists need to do more research on this topic in other populations.

A later study showed that females with DID had significantly decreased thickness and surface area of their brain in particular regions compared with controls.

The brain cortex was thinner in regions known as the insula, anterior cingulate, and parietal cortex regions. The surface area of the brain was reduced in the temporal and orbitofrontal cortices.

These studies suggest that trauma can actually change the shape of your brain, with implications on your memory, behavior, and sense of self.

DID is strongly associated with childhood trauma, especially abuse from a caregiver. But everyone is different. So for two people who have a similar experiences, one might develop DID while the other doesn’t.

There are many factors that can play into someone developing DID and how it affects your thinking and behaviors. These factors include family, social influences, and culture.

It’s possible that your genes could predispose you to having DID, but there’s no research that currently shows this.

One review article from 2017 about the causes of DID noted that there was relatively little research on the condition to date.

The authors said researchers hadn’t yet investigated potential genetic and epigenetic factors. With epigenetic factors, the experiences and behaviors of your parents and ancestors can influence the function of the genes they pass down to you.

The authors of the review said scientists needed to do more research to investigate whether a person with DID might carry genes that can influence if they develop the condition or not.

This is particularly promising because studies have already shown that genes can influence dissociative disorders in general.

If you’re living with DID, your mind has learned to dissociate. Dissociation is a mental state in which a person mentally separates themselves from the world around them.

In a dissociative disorder like DID, this separation has become involuntary. In fact, may people with DID aren’t aware they have one or more personalities.

Many healthcare professionals use criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to diagnose DID.

According to the DSM-5, the symptoms of DID include:

  • Multiple alters control your behavior. Your actions, opinions, memory, tone of voice, and emotional profile may change depending on which alter is in control. You or other people may observe these signs.
  • Memory loss or amnesia. You might have gaps in your memory, forget personal information, or find yourself somewhere without remembering how you got there.
  • There isn’t a more likely explanation. The identity disturbances aren’t caused by normal social or cultural practices, such as imaginary play in children.
  • Substance use isn’t the cause. While people with DID may use substances, this isn’t the cause of the personality changes or identity disturbances.

DID often occurs alongside other conditions. In addition to DID symptoms, you may also have:

If you think you or someone you know may be living with DID, it can help to start by speaking with a psychotherapist who has experience treating dissociative disorders.

To do this, you could start by asking your primary doctor to recommend a therapist, or you could search for an expert online. If you’re in the United States, you can use the American Psychological Association’s search tool.

NAMI also provides a helpful list of resources where you can get help for DID.

Once you’ve reached out to a trained healthcare professional, they’ll ask you a series of questions to assess your symptoms. If you can, tell them about specific instances when you had symptoms, as well as what people close to you have said.

If you’re living with DID, a professional may recommend psychotherapy or hypnosis. The goal of therapy is to help you deal with your trauma and unite your alters into one identity.

A therapist may attempt to talk with your alters and help them work through feelings and experiences. Trauma may be behind the feelings and behaviors, so a therapist might try to uncover these traumatic memories so you can heal.

Therapists will always try to treat the root cause of a condition.

Dissociation can also be a symptom of other mental health conditions such as borderline personality disorder (BPD) or post-traumatic stress disorder (PTSD). If they think you may have symptoms of one of these, they’ll look into treating those conditions.