A snowy evening…
During my sophomore year of high school, I narrowly missed a head-on collision with a semi. I was driving after school to a cello lesson in a neighboring town about 40 minutes away. It was late February, snowing, and the roads were terrible. Coming into a curve on the narrow two-lane highway, a semi crossed the center line into my lane. Quickly trying to avoid the crash, I swerved to avoid the truck and ended up fishtailing before sliding off of the highway into the ditch. I was shaken up, but physically ok. While this experience was traumatic and definitely taught me the value of snow tires and driving slowly, I did not develop any lasting symptoms. So why do some people develop lasting symptoms after traumatic experiences while others do not?
Inside the Brain
While our brains are truly remarkable machines in so many respects, they’re fundamentally focused on finding the way to keep us alive while expending as little energy as possible. So, when you experience a stressful, sudden event, your brain activates the fight or flight response. A rush of hormones including adrenaline and glucocorticoids is released to help you survive. In my case, the adrenaline kicked in, and before I’d even processed that I was in danger, my foot was on the brake and I was pointed towards the ditch. At the same time, glucocorticoids were released in my hippocampus, a brain structure critical in memory formation, so that my brain could form a memory of the event. These glucocorticoids help trigger memory formation by beginning a cascade of signals within neurons resulting in modifications to histones, a family of proteins that help store and organize your DNA. These modified histones expose specific regions of your DNA to allow for glucocorticoid-induced transcription of Immediate-Early genes (IEGs), resulting in protein synthesis. These IEG proteins play critical roles in memory formation, though exactly how that works is still not fully understood. Interestingly and critically, the level of glucocorticoids released in the hippocampus directly relates to both how many IEG proteins are made and how strong of a memory you make of that stressful event. Through a process known as long-term potentiation (LTP), your brain changes and adapt to your own life experiences. Making memories of dangerous and stressful events is important because it can help keep you alive in the future by reminding you of past events. However, when these memories are too strong, sustained LTP activation of stressful memories can result in lasting symptoms of PTSD.
What can be done?
For people living with PTSD, there are effective, research-supported treatment options. Pharmacologically, selective serotonin reuptake inhibitors (SSRIs) are commonly used. This class of medication blocks the reuptake of serotonin, allowing for more serotonin to be present in the brain for a longer period of time. While decisions about how to treat PTSD should always be made in consultation with a physician or therapist, some common non-pharmacologic treatments are:
- Prolonged Exposure
- Cognitive Processing Therapy
- Cognitive-Restructuring Therapy
- Eye Movement Desensitization and Reprocessing
Conclusion
While this does offer some explanation for why some people do or don’t develop PTSD symptoms, much more research is needed. Science does not have all the answers but does have a dearth of unexplored questions and new avenues of investigation to help unearth more data and find answers.
