Your Brain and Dissociative Identity Disorder

You struggle with the devastating symptoms of dissociative identity disorder (DID), dealing with the emotional, relational, and economic consequences every day. However, have you ever wondered what is going on in your brain when you live with dissociative identity disorder?  

This article will explore how the brain is affected by DID and where these brain malfunctions originate.

Defining Childhood Trauma

One cannot discuss the diagnosis of Dissociative Identity Disorder without first talking about psychological trauma. The Diagnostic and Statistical Manual of Mental Disorders (DSM) defines psychological trauma as:

“The direct personal experience of an event that involves actual or threatened death or serious injury; threat to one’s physical integrity, witnessing an event that involves the above experience, learning about unexpected or violent death, serious harm, or threat of death, or injury experienced by a family member or close associate. Memories associated with trauma are implicit, pre-verbal, and cannot be recalled, but can be triggered by stimuli from the in vivo (within the living person’s) environment. The person’s response to aversive details of traumatic event involve intense fear, helplessness, or horror. In children, it is manifested as disorganized or agitative behaviors.” 

As you can see, this definition is very broad. There are several key elements worthy of mentioning; however, “the person sees or fears death or severe injury and a threat to their body.” Also, please note that they have listed as a response to these emotionally stimulating events intense fear, helplessness, or horror. A person who has been traumatized may experience many of the following psychological and physical symptoms: 

  • Shock, denial, or disbelief
  • Confusion, difficulty concentrating
  • Anger, irritability, mood swings
  • Anxiety and fear
  • Guilt, shame, self-blame
  • Withdrawing from others
  • Feeling sad or hopeless
  • Feeling disconnected or numb  
  • Insomnia or nightmares
  • Fatigue
  • Being startled easily
  • Racing heartbeat
  • Edginess and agitation
  • Aches and pains
  • Muscle tension 

Childhood trauma forever changes who children are as they grow into adulthood, and as we shall see further on, changes us physically as well.

Average Brain Anatomy and Function

To understand what goes wrong with the brains of children who are exposed to repeated and horrific trauma, we must first understand a little bit about brain anatomy.

Basically, the brain is divided up into three centers, each controlling a different aspect of who we are and our behavior. They work together to help us interpret and interact with our environment. They are the survival center, the emotional center, and the executive center.

The Survival Center. This part of the brain is also titled the reptilian brain or brainstem and is the most primitive part of the human brain. Fully developed when we are born, it handles all our basic instincts and functions to sustain life and to help us move about in our world. It controls our breathing, digestion, heartbeat, hunger, all the things we do without having to consciously think about it. This part of our brain is also responsible for our fight/flight/or freeze response to perceived danger. When it receives signals that it understands to be dangerous from the senses (sight, smell, sound, touch), it reacts quickly and automatically.

The Emotional Center. This part of the brain is titled the limbic system. Its function is to process memory, emotions, and responses to stress. It is responsible for our ability to nurture and care for others as well as separation anxiety, fear, rage, and bonding. It also regulates control over our hormones. The limbic system is the seat of our emotions, where we process memories that are emotionally charged.

The two structures we will focus on later in this book are the hippocampus and amygdala, two important parts of the brain that, as you will see, are heavily affected by trauma. 

The Executive Center. The prefrontal cortex is also known as the thinking brain. It is responsible for our rational thought processes such as problem-solving, planning, creativity, and self-awareness. It also helps us interpret our emotions.

It is important and interesting to note that the things we interpret in our day to day lives flow through our brains in much same order as listed above. First, our senses are activated to tell our brain stem that we need to pay attention, next the limbic system reacts to the new stimuli as dangerous or no. It is the thinking brain that reacts last, perhaps seconds to minutes later. So, we can become afraid of a stimulus, say a spider, and react before we are able to think about our actions.

The Non-Traumatized Brain and Fright

Everyone has experienced the feeling of stage fright from being in front of a group of people to sing or talk and feeling an overwhelming feeling of fear. This feeling is being brought to you by way of the two almond-shaped masses of tissues deep in the brain called the amygdala mentioned in a former chapter. In these parts of your brain, the size of thumbnails is centered in the control of autonomic responses normally associated with fear, arousal, and emotional stimulation. 

The amygdala is necessary for the decoding of emotions, especially threatening stimuli. This will stimuli reach the amygdala, also discussed in a former chapter, by two different highways. Each of these pathways complements the other. A short, and not too precise method, comes from the thalamus which allows us to prepare for potential danger before knowing exactly what the danger is, and a longer route comes from the medial prefrontal cortex aka the area of the brain involved in the final phase of fear reaction to danger the choice of action to avoid it.

Fear and anxiety are not, as one might think, intrinsically linked. Instead, they are distinctly different emotions. Fear is a physical response to danger where anxiety is a psychological response to perceived danger.  

For example, You see a spider (assuming you are afraid of them), and fear response is triggered. Anxiety is a feeling of being at risk but in no real danger.

However, fear causes you to jump and leave the room because you have perceived danger and acted before giving it deeper thought. 

Fear and anxiety come from different regions of the amygdala with fear emanating from the central nucleus, the area responsible for commands for bodily responses to fear and anxiety coming from the area responsible for emotions that causes slower, longer-lasting responses that may last long after the threat ends.

The Effects of Stress Hormones on the Developing Brain

The chemicals that we make in response to stress are important to our being able to escape or confront danger, however, when the developing brain of a young child is bathed in stress hormones and never return to normal levels, the results can be disastrous. Such is the case in children who live in traumatic environments where they are in constant danger physically, emotionally, or sexually.

What hasn’t been discussed thus far is the fact that the brain is divided into two hemispheres or halves, right and left, each responsible for the separate ways we store the information we receive from three varied parts of our thinking brain.

The main functions of the left hemisphere include language, math, and logic. The right side regulates our ability to determine special differences in our environment, face recognition, visual imagery, and music. These functions are settled forever on one side or the other, rather we can reroute what we need to when one side becomes damaged. This been observed in people who have brain injuries from accidents, disease, and stroke.

During the development of a child’s brain from birth to around five years, extensive changes to the size of the brain and the number of neurons with their connectedness occur.

Myelination. We create myelin to increase the size of the brain by creating layers around brain cells, and this increases the speed of information that can be processed.

Neurons (brain cells) connect to each other and communicate, and this connectedness is dependent on our childhood experiences. We start out at birth with many more brain cells than we need and prune them once new connections are established.

These changes that occur in the brain during development are called plasticity, and this nature decreases over time. An interesting and important aspect is that the decrease in plasticity over time is different for different systems in the brain. Some areas of the cortex continue to reorganize with experience until late in life, while others such as language centers are less likely to change.

Trauma affects this normal development of the brain by interrupting through overstimulation of stress hormones, the ability of the brain to process memory, and the two hemispheres of the brain to communicate. While the survival center (brain stem) continues to keep us alive, the emotional center cannot regulate correctly what memories are stores there, and the hemispheres of the brain become fragmented in their ability to store information. These changes are not reversible.

Although the exact mechanism of what occurs in the formation of alternate egos is not well understood, severe and repeated trauma that occurs before the age of about five is thought to be a vital factor to what leads to the development of Dissociative Identity Disorder.

Stress Hormones (Neurotransmitters)

To fully understand what severe and repeated trauma does to the brains of young children, one must first learn some about the chemicals neurons (brain nerve cells) use to communicate called neurotransmitters and the brain structures most affected by them.

There are many important substances responsible for the activity in our brains, but we shall touch on just a few of these important chemicals and hormones.

Cortisol. Cortisol is a hormone that controls our reactions to stress. This stimulant gives us the energy to fight or flee in the face of danger.

Serotonin and Dopamine. These are neurotransmitters that affect our moods and behaviors. These chemicals trigger an increase in heart rate, blood pressure, and reduces blood flow to the gut. It also inhibits the body from releasing bodily wastes such as urine and feces. These responses are important to be ready to face danger.

Norepinephrine and Epinephrine. These neurotransmitters affect mood, behavior, and create the fight/flight/freeze response. This chemical mobilizes the brain and body for action by stimulating the necessary areas of the body needed to fight or flee. It is responsible for raising awareness, alertness, and vigilance.  It also enhances the formation and retrieval of memory, focuses attention, increases restlessness, and anxiety.

Glutamate. Glutamate is a neurotransmitter that excites nerve cells. In balance, it is required to organize our perception of our experiences.

Under normal circumstances, these chemicals allow us to move about in our environment very well. However, when young children experience repeated and extreme traumatic events, the production of these chemicals is altered. Levels of cortisol are decreased, norepinephrine and epinephrine are elevated, and Serotonin decreases.

Prolonged exposure, such as in repeated and severe childhood trauma, can have dire consequences. There can be behavioral changes such as depression, fear, and lack of impulse control. Also, there can be an impaired perception of reality and changed the filing of memories.

Because of the existence of severe and repeated trauma, the imbalance of these chemicals interferes with the storage of declarative memories, so the child may not remember what happened, or if they do they do not remember correctly. The sizes of the parts of the brain can be altered by continual bathing in the above substances, causing life-long changes that can alter the future of the traumatized child’s life.  

Brain Structure Changes Caused by Trauma

The constant submersion of a child’s brain in stress hormones can change a child’s brain and its ability to function forever.

One researcher, Martin Teicher, has found evidence of how a person’s brain is affected by childhood trauma. In 1993, he found brain abnormalities in 54% of children with histories of physical abuse, but only 27% in children who had no history of abuse. The numbers jump alarmingly when measuring children who have been sexually abused. The research showed 72% of children with histories of this type of abuse with abnormal brains. (Teicher, 1993). The regions found to be most affected by trauma, not only in Teicher’s work but in subsequent research are as follows:

  • The Hippocampus. This part of our brains is responsible for declarative memory, emotions, and critical for learning. It allows us to process memories and manage the emotions that go along with them. Research has found a reduction in the size of the hippocampi of adults who were severely traumatized as children of 19%.
  • The Amygdala. This structure is responsible for the unconscious storage and processing of emotions and initiating the flight/fight/freeze response. The amygdalae of adults who were exposed to extreme and repeated trauma as children are often hypersensitive to the information received through the senses and can trigger a strong fear response even when there is currently no danger present.

Through the years since Dr. Teicher first found that a child’s brain development can be severely curtailed by trauma, there has been much research and many papers written that back up his assumptions and findings.

A Failure to Communicate

The hippocampus and amygdala are meant to work together to form a cohesive memory of events. When there is extreme and repeated trauma in childhood, this communication is disrupted. Memories can either be enhanced or totally repressed, depending on the way these two vital parts of the brain interact.

There are many effects caused by this disruption of communication. One is the dysregulation of emotions. Since the amygdala senses danger when there is none, the hippocampus is hard-pressed to respond appropriately. Temper tantrums and crying spells are caused by the continual bombardment of the amygdala. Because these two structures are diminished in size, depression, anxiety, and irritability are often seen. 

Summing Up the Damages

Having grown up into adulthood after experiencing childhood trauma, multiples face a plethora of problems. When we experience distress, such as intense fear, there are many instinctual reactions our bodies and brains undergo to ready you for fight or flight.

First, your amygdala perceives a situation that it senses as extreme danger. Immediately it chemically triggers a stress response by sending a signal to the hypothalamus and pituitary gland (both are also located in your brain). Your brain then sends nerve signals down the spinal cord to the adrenal glands telling them to release the hormone adrenaline to increase the amount of sugar in your blood and to raise your blood pressure.

The brain’s hypothalamus also sends signals to the pituitary gland telling it to release a very important stress hormone known as cortisol. This chemical is responsible for making you ready to escape from the perceived danger.  

All the above reactions of your brain to stress are normal and vital to survival in a world where danger literally can lurk around every corner.

The problem comes when these responses go on for weeks or years. The raised levels of cortisol can do major damage to the immune system and damage the brain’s ability to adapt, including impairing a person’s memory.

Not only is memory impaired, but the structures of the limbic system (the parts of the brain in the picture in a previous chapter which control emotion and memory) can become damaged. Many (if not most) people with diagnosed DID have smaller than usual volumes of amygdala and hippocampal tissue.

Missing a Milestone

Perhaps the most devastating effect that childhood trauma has had on the brains of multiples is that we missed a vital milestone. Milestones are benchmarks that all children go through in their development, such as the development of speech. Before the age of seven, children are capable of learning any language rather easily as they have not reached the cut-off point for doing so. After age seven, learning a new language becomes more and more difficult as time passes.

If, however, a child is neglected without hearing a language being spoken until the age of fourteen (early adolescence), the child will never be able to develop a normal language pattern and speak any language fluently.

Becoming a whole personality is also a milestone that children normally achieve around the ages of 5 to 7 years. There is no leeway for a child’s development of a whole personality after this benchmark is passed. The child, who was born a dissociated personality, never reaches the ability to coalesce as one whole person. Instead, the personality remains dissociated, and this dissociation is used to survive the unthinkable circumstances that a child may find themselves surviving.

Once one understands that we are not going to coalesce into one whole complete personality, we can work on getting as close to that ideal as is possible. We can learn, as multiples, to live in harmony with ourselves and learn cooperation and co-consciousness so that the problems before we learned these lessons die down and even disappear.

Ending Our Time Together

None of what I’ve spoken about in this article means that we multiples are strange or extraordinary people. Our brains reacted to what we went through in the only way it could ultimately lead to us being dissociated in our personalities.

However, we are not freaks, nor are we strange. We are totally and completely normal for where we have been.

Take this information I’ve offered you today and use it to understand yourself better. It is always better not to be a mystery to oneself, and I’m hoping the information in this article relieves you of the burden of not knowing how you became a multiple beyond knowing you were brutally traumatized as kids.

Keep your heads up, you are special to me, and the world is a better place because you survived to enrich it.

“What sets you apart can sometimes feel like a burden, and it’s not. And a lot of the time, it’s what makes you great.” ~ Emma Stone

“The most incredible beauty and the most satisfying way of life come from affirming your own uniqueness.” ~ Jane Fonda


Teicher, M. H., & Samson, J. A. (2016). Annual research review: enduring neurobiological effects of childhood abuse and neglect. Journal of child psychology and psychiatry, 57(3), 241-266.

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