Approximately 50–60% of people report having at least one traumatic event in their lifetime. Not all traumatic events cause Post-Traumatic Stress Disorder (PTSD), but even in those who recover, it is common for symptoms to develop in the days and weeks that follow. These symptoms might be flashbacks, nightmares, feeling numb and detached from people, and avoidance of trauma reminders. Obviously, people who work as first responders (soldiers, police, paramedics, fire fighters, etc.) are more likely to experience traumatic events and develop PTSD because they are more likely to experience or witness a trauma. Other typical causes of PTSD include physical and sexual assault, motor vehicle accidents and workplace injuries.

Fortunately, for many people these initial PTSD symptoms decline naturally in the 3–6 months following the event. However, anywhere from 5% to 30% of sufferers will actually develop chronic PTSD.

In the movies, characters who have PTSD (like a soldier home from war) are usually startled by loud sounds, or the director might show jumbled images that are supposed to represent flashbacks to the trauma.

These movie scenes are true and accurate, but come nowhere near the real range of intrusive thoughts and memories that get triggered in those with PTSD.

First, there are the more ‘obvious’ memories and thoughts associated with a traumatic event — seeing a dead body and blood, or hearing gunshots. However, it can sometimes be the ‘less obvious’ and banal things that get traumatically remembered — gasoline, smoke, article of clothing, someone’s facial features, or even common smells like cleaning products (accidents and crime scenes need to be cleaned and sanitized at some point).

When getting robbed at gunpoint, someone with PTSD might remember a facial feature of the criminal (“I’ll never forget his teeth and smile”) as much as they remember the gun.

The point is that traumatic events can “burn” memories into the brain that cause unwanted thoughts and images to pop into the person’s head. It also makes them want to avoid things associated with the memory.

How the Brain Changes Following a Trauma

Not only does PTSD produce memories that are highly disturbing and intrusive, but it also tends to change the person’s fundamental beliefs. For example, they might have negative beliefs about:

· Themselves (“I will never be the same person”)

· Other people (“People are dangerous ”)

· The world (“I need to stay alert in this dangerous world”)

· Work activities (“The risk of dying in my job is very high”)

· Basic activities (“The risk of dying while driving is very high”)

It is this combination of haunting memories and new beliefs that play a large causal role in someone developing PTSD.

Another consequence of trauma is the brain becomes hypervigilant for threat in the environment. The person doesn’t have to try and find threats, their brain is automatically scanning everywhere for potential risks. While walking around the mall, a paramedic might start to notice the faces of people most likely to suffer a heart attack. A veteran soldier will feel very uncomfortable if people are sitting behind them at a restaurant. Someone who has been mauled by a dog will get jumpy whenever any small animal comes into view.

There are a number of other mental changes that occur, and would take some time to review each in detail. It suffices to say that the brain of someone who has experienced or witnessed something traumatic is not the same organ as before the tragedy. As such, it can be difficult for some to understand how a talking treatment like Cognitive-Behavioural Therapy (CBT) can change this mess of wiring in the brain. Well, therapy can fix it and do it better than any other treatment option.

Can We Erase The Mental Scars?

In the past number of years, scientists have been working to develop treatments that would erase traumatic memories. They have had some initial success in studies with rats. For example, one recent study showed that exposing rats to a gas called Xenon appeared to erase their fear memories. This type of research is still in the early stages, and there are no treatments at this time that allow us to erase the traumatic memories of PTSD sufferers. Although, I continue to see occasional news items reporting new findings.

In the meantime, CBT has large and positive effects for those with PTSD. For example, psychologists have learned a lot about the causes of fear and traumatic memories, based on hundreds (if not thousands) of research studies. They’ve used this knowledge to develop and hone our treatment of the disorder.

One of the findings from this research is that we never really erase memories through therapy. During a traumatic event, the brain seems to create a number of very strong connections between fear/trauma and various things present during the trauma (ex: image of a gun, smell of smoke, sound of someone screaming, etc.).

For example, a police officer who witnesses a suicide via gunshot to the head, might develop a whole memory system that links the following things with fear:

· Guns

· A type of sweater (similar to the one worn by victim)

· Blood

· Certain verbal expression (if the victim said “Life sucks” or “I’m outta here” just before pulling the trigger)

· A particular facial expression of squeezing eyes closed (victim did this before shooting)

Now, the police officer has intrusive thoughts about the trauma whenever his son squeezes his eyes shut or when he sees someone wearing a certain sweater.

He also is more likely to avoid things like TV shows with violence.

Victims of PTSD work hard to avoid things associated with the trauma, and this is partly why it is a mental disorder — the avoidance interrupts their life and makes the anxiety worse. The only way to conquer any anxiety problem is to face the fear in some way. However, there is a right way and wrong way to do this, which is where CBT comes in — by using a procedure called “exposure.”

Facing the Trauma and Putting it All Back Together

When psychologists use exposure they have the person face the very things that remind them of the trauma. They look at images, watch videos, smell objects, and hear sounds that cause them to feel anxious.

Sound cruel and unusual? That is sometimes the reaction of some of my clients — “why would I do that when I am trying to forget this stuff?”

We use exposure techniques because we are trying to build a new set of memories — what many professionals call a “safety memory.” Let me explain.

Think about the police officer from the previous example. Prior to the trauma, things like guns, sweaters, facial expressions and even blood didn’t bother him. In fact, these things usually don’t cause much fear in most people. This is where we want to return — to having all the things in the “fear/ trauma memory” go back to normal.

The research shows that we do this by using exposure therapy in safe settings (ex: therapists office) and in a particular way that allows new memories to form. Over the course of sessions and repeated exposures to all kinds of feared stimuli, things like the sweater develop new and strong associations with safety and normalcy.

Now, does the old, fear/trauma memory disappear? No, it does not. What seems to happen is that the new “safety memory” that gets developed in therapy inhibits or prevents the old memory from getting activated. In fact, over time and in certain settings the old memories might get triggered again, even when therapy is successful. This doesn’t mean therapy has failed — in fact, most experienced psychologists anticipate these situations and develop a plan with the client.

In terms of the PTSD beliefs that get developed after the trauma, part of CBT involves working to change these as well to something more healthy and adaptive. Sweaters and facial expressions return to being just sweaters and facial expressions.

So, for those suffering from PTSD, science has yet to find a treatment that allows us to erase those memories, but fortunately psychologists have the next best things — a treatment that rewires your memory systems and changes traumatic beliefs. This allows PTSD sufferers to get rid of those difficult symptoms and get on with their lives.

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