system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do our brains suppress traumatic experiences? And why?

For example, if something awful happens to you as a kid but you thought you weren’t affected by it, how does it come out in other forms later?
gpt
Actually, from what I've read, the idea that people tend to suppress traumatic memories isn't scientifically supported.  
To cite: "The 1980s saw the peak of an idea that was never based in science: the notion that people can suppress memories of traumatic events and those repressed memories can manifest as seemingly unconnected mental health issues, such as anxiety or eating disorders. The idea was popularized by the book The Courage to Heal (1988), in which the authors took the position that their therapy clients, especially women, who had such issues should be encouraged to recover memories of abuse, and if such memories could be dredged up, then they were real. 

The concept of repressed memories led in part to the satanic panic of the 1980s, and many of those subjected to recovering techniques “remembered” not only being abused but also being part of satanic ritual abuse. 

Recovered memory syndrome was a massive failure on the part of the mental health profession. The ideas, which were extraordinary, were never empirically demonstrated. Further, basic questions were insufficiently asked: Is there any empirical evidence to support the incredible events emerging from therapy, for example? Is it possible that the recovered memories are an artifact of therapy and are not real? 

Now, with three decades of hindsight, we can say a few things with a high degree of confidence. Recovered memory syndrome is mostly, if not entirely, a fiction. People generally do not repress memories of extreme trauma (the existence of rare exceptions remains controversial). Further, as Elizabeth Loftus pointed out, memories are constructed and malleable things. Also, independent investigations by the FBI, other law enforcement agencies, and scholars never found any evidence of the satanic ritual abuse, murders, and other atrocities emerging in recovered memory sessions. The events simply never happened. 

What emerged from the entire sad episode was an increased understanding of what is now called false memory syndrome, the construction of entirely fake memories. This is accomplished through guided imagery, hypnosis, suggestion, and group pressure. These techniques violate one of the basic rules of investigation: Never lead someone by putting words in their mouth. This is especially important if the person is vulnerable and confused. 

While there is some legitimate controversy over whether it is even possible to repress such memories and accurately recall them later, there is no question that the massive repressed-memory industry of the 1980s and ’90s was not evidence-based."