Childhood trauma could look like a personality disorder, or as an emotionally dysfunctional person, or as a “broken” person, or as someone with many diagnoses and comorbidities.
A child that develops trauma in childhood, will suffer from Developmental Trauma, or from Attachment Trauma, or both.
Developmental trauma has many debilitating consequences in the normal growth of the child that could have severe consequences in adulthood.
Developmental trauma occurs when the brain and nervous system are forming which means that many of the processes will be hijacked by the autonomic nervous system due to the activation of the survival mode.
Developmental trauma Is interpersonal in nature – involves harm or abandonment by caregivers or other responsible adults; is repetitive or prolonged, such as child abuse and neglect; may produce guilt or shame, as children may have wished to take protective action (e.g., fight, run) which they were unable to do at the time; and is associated with compensatory behavior in adolescence and adulthood like substance use, smoking, high-risk behavior, etc.
Because of compromised growth of the system, the adult will suffer from a series of alterations.
This list includes just a few:
Brain:
brain structure: overactive amygdala, atrophy of the prefrontal cortex, diminished hypo campus, etc.
brain circuitry, brain waves, and neural connectivity: reduce communication between neurons, modification of their response
neuro-chemical: neurotransmitters, endocrine system, inflammation: over or underproduction of some of them.
Memory
fragmented memories: remember what brings acute responses, forgets the parts that will create context.
memory disruption: long-term-short term, implicit-explicit. The narrative stops making sense.
Chemistry: excessive stress response.
Physiological (medical):
Digestive system
Autoimmune system
Metabolic system
The way Trauma changes a person:
Trauma has an impact on every level on the mind/body of a person that suffers from it. Therefore, there are many changes. That’s why I say that when someone heals from trauma, s[he] recovers his/her life.
I’ll mention many of the changes from different angles, but first, let's agree on something. Your question says “a trauma” and I want to make sure you don’t confuse a traumatic event with the disorder “Trauma”. Experiencing a traumatic event doesn’t necessarily end up developing a mental illness. Experiencing a traumatic disorder can change you but not significantly, and most importantly, not permanently. If you want to understand why, look for my answer to the question “How much do traumatic experiences as a child affect people as an adult?” Having said that, let's respond to the question: “How can Trauma change a person”
When trauma has developed as a mental disorder, many changes in the physiology and functions of the different systems of the body become the “new” way to operate for your system. This happens because after the traumatic event and the consequent traumatization period (freeze-fight-flight-submit-collapse) the brain makes a huge amount of adjustments including the assignment of energy to where it’s more needed. Some organs will get more energy than others, and some parts of the brain will get less activation than others; all due to keeping working in the task of surviving. Those changes become an adaptation of how your system is going to work from then on. That adaptation is detrimental to almost everything you will experience in the future; from the way you breathe, to the way you digest your food, to how you behave, and how you think others treat you.
Just to give you an idea, this is a list of the alterations that happen with trauma. When I say “alterations,” I’m referring to the fact that what I’m listing will be not working as they should. If the alteration happens for a prolonged period of time, more and more functions will be affected: some organs will get exhausted or worn-out, some functions will be diminished, some development will be compromised, some unhealthy behaviors will become habits or automatic reactions, some medical problems will appear.
Biological Alterations
Brain:
brain structure: overactive amygdala, atrophy of the prefrontal cortex, diminished hypo campus, etc.
brain circuitry, brain waves, and neural connectivity: reduce communication between neurons, modification of their response
neuro-chemical: neurotransmitters, endocrine system, inflammation: over or underproduction of some of them.
Memory
fragmented memories: remember what brings acute responses, forgets the parts that will create context.
memory disruption: long-term-short term, implicit-explicit. The narrative stops making sense.
Chemistry: excessive stress response.
Physiological (medical):
Digestive system
Autoimmune system
Metabolic system
Psychological alterations
Perception distortion
Loss of sense of self
Interoception
Somatic states
Personality distress and fragmentation
Loss of Resilience
Emotional dysregulation
Social Alterations
Social behavior
Personality distortion
Self-destructive behavior
Interpersonal difficulties
Spiritual alterations
That list may not make much sense alone since each item a lot of explanation, but I wanted to give you an idea of how much we change. To make it simpler, I can say that the main changes manifest as:
Intrusive memories: flashbacks, nightmares, “hallucinations”
Negative changes in thinking and mood: extreme emotions and overreactions, rapid shifts from one feeling state to another —calm then terrified, reasonable then enraged— hopelessness, memory problems, detachment, numbness, demotivation, anhedonia, emotional flatlining, distortion of reality, chattered sense of self and identity.
Changes in physical and emotional reactions: rapids shifts in attitudes towards others— “I love you. I hate you,”— hypervigilance, self-destructive behavior —like drinking, over-eating, using drugs as a way to scape and soothing,— trouble sleeping and concentrating, irritability, paranoia, restlessness, overwhelming guilt or shame, impulsivity, depression-lack of energy, physical symptoms with no medical cause, etc.
Dissociation: alterations in consciousness, alterations in self-perception.
To summarize, the changes that the system had to make in order to keep your body alive can destroy your life. Our system has very primitive defenses and doesn’t understand well-being. It only cares about surviving even at the cost of the quality of your life. It’s imperative to reverse your system to optimal functioning in order to proceed to repair the sequelae left in your perception and your sense of who you are. Healing is possible. The secret is to take control over your life instead of letting your primitive defenses to decide for you.