I wanted to address some of the differences between alcohol-induced memory loss, which we discussed recently, and memory loss associated with the effects of trauma. My interest in the subject began with a tragic case some years ago in which both may well have been at work.

The case: New parents had entrusted the care of their infant to an adolescent relative. The parents were to be gone all that afternoon, and at some point the young babysitter, probably bored, located an opened bottle of wine and poured herself a drink. It appears she went on to consume about half the bottle in a couple of hours before passing out on the couch. Something– no one knew precisely what– must have happened, and the child died. The parents returned home to this discovery. The child’s mother screamed and briefly fainted.

When the EMT’s arrived and woke the drinker, she was unable to recall anything beyond that first glass of wine. I’m told those memories never returned. The child’s mother, on the other hand, continued to have nightmares and “flashbacks” of her child’s face at the moment she saw it. The rest of the incident — such as the arrival of an ambulance and the police — she couldn’t recall.

She was later diagnosed and treated for PTSD.

The effects of trauma on memory are quite different from those of an alcoholic blackout. Some of the differences:

  • Trauma actually appears to enhance certain memories, making them clearer and more vivid. That applies to some but not all memories, by the way. We might characterize this enhancement as selective.
  • Because trauma is, by its nature, a negative emotional experience– accompanied by terror, rage, etc.– traumatic experiences are far more easily recalled than a positive experience. We might say that memories of trauma are notably “sticky”.

Individual differences affect how people respond to trauma, but any experience that triggers a strong fight/flight response could perhaps imprint the memory. Even years later, traumatic memories are known to resurface quickly, in response to a cue or trigger in the environment. As one patient put it, immediately following a flashback, “I felt the way I did the moment it first happened. Even though that was years ago.”

Unlike the usual television portrayal of PTSD, most suffering is done in silence. In fact, it’s often difficult to convince the trauma patient to seek treatment, in part because of fear of having to re-experience the trauma. Still, left untreated, trauma can be a major factor in depression and anxiety disorders. Treatment can help.

Oh, about the loss of details when recalling a trauma: that’s common. The theory is that the core incident– the attack, the explosion, the accident, the abuse– draws the individual’s focus to a point where the context, the surrounding details, are pushed from awareness. They fade rapidly. It’s as if the information never makes it all the way into longer term memory.