Mnemosyne vs. Lethe

Throughout history and across cultures, the force of memory has always held a prominent position in our concept of humanity and self.  The ancient Greeks embodied memory in a goddess – Mnemosyne, the mother of the nine inspiring Muses.  But what if a person possessed memories so upsetting and intense that they caused him to not be able to function as himself?  If you had the option, would you choose to forget or to distance yourself?  This dilemma is now a source of debate among scientists and medical practitioners.  Propranolol, a drug previously prescribed to people suffering from hypertension, has also been found to bring some relief to victims of traumatic events my manipulating their memory of the experience.

            When a person experiences a highly emotional or traumatic event, their memory of it is far more vivid than that of a mundane occurrence.  We tend to think of such moments as something to treasure, or a defining experience that, even if painful, contributes to who we are.  However, there is also a biological reason for the strength of such a memory.  While a person feels heightened emotions, the sympathetic nervous system causes the adrenal glands to release epinephrine (adrenaline) and other stress hormones that enter the blood stream and contribute to the physical symptoms of fear - wide eyes, sweating, fast pulse, and dilation of blood vessels in larger muscles (6) - as well as reactions in the amygdala and hippocampus (two parts of the brain responsible for memory).  “Stress hormones activate adrenergic receptors in the basolateral amygdala, which modulates the effect of these hormones on hippocampal consolidation [of memory]” (7).  The amygdala deals with responding to emotional stimuli, especially fear, by enhancing perception, and sending information of that nature to the hippocampus.  The hippocampus is the part of the human brain that seems to be in charge of forming and storing short and long term memories.  “By influencing perception and attention, the amygdala can alter the encoding of hippocampal-dependent, episodic memory, such that emotional events receive priority” (7).  Essentially, memories that involve strong emotional stimuli, through the interaction of the sympathetic nervous system, the amygdala, and the hippocampus, are more intensely imprinted onto the human mind in “neurological ink” (5). 

            Posttraumatic stress disorder (PTSD) is a condition that some victims or survivors of traumatic experiences may develop when their memories are too intense – when the amygdala made them too powerful.  PTSD is characterized by “vivid recollections of the horrific events they survived or witnessed – wars, rapes, accidents, injuries, concentration camp internments – often return relentlessly for years, evoking the same fear, helplessness, horror and consequent anguish that accompanied the initial experience.  This creates a disabling cycle that can be difficult, if not impossible, to break” (1).  Some patients also suffer from detachment from loved ones, and sleep problems such as nightmares or insomnia (4).  Every time a PTSD patient “relives the traumatic experiences”, the memory is strengthened by stress hormones pumping through the brain again – rather like reviewing emotionally intense flash cards (1). There are different degrees of PTSD as with any other illness.  About eight percent of the population of the United States will suffer from PTSD in their lifetime, and it is twice as probable for women to develop the condition (5).  Seeking therapy from psychiatrists has been effective for some patients, but is viewed as insufficient by others.  However, more opportunities for treatment may be on the horizon with the research being conducted by scientists on a beta-blocker drug called propranolol.

            Previously, propranolol has been used successfully to treat hypertension.  Recent research has shown that beta-blockers prevent some stress hormones like epinephrine from being released onto the memory forming parts of the brain such as the amygdala and hippocampus (5).  Similarly, their effects as hypertension drugs – decreasing heart rate and others – also lessen the physical effects of emotional stress (4).  As a result, patients would not forget the traumatizing event, but the memory of it would be less powerful.  As psychiatry professor Roger K. Pitman of Harvard Medical School states, propranolol would “reduce the intensity of the memories to a more normal level, a level that a person can easily live with” (2).  By inhibiting the chemical stimuli that accompany emotion, the memory is recorded as mundane rather than extraordinary or disturbing and becomes vulnerable to the potential cloudiness that causes a person to forget what they did with their keys.

            There have been many studies conducted on the effects of propranolol on the formation of memory.  One such study conducted by James L. McGaugh and Larry Cahill, both neurobiologists at University of California, Irvine, in the late 1990s examined subjects’ memories of different types of stories.  The first group of people “were told an emotionally neutral, comparatively boring story” (5).  The second test group heard a far more emotional story about a boy that had suffered a serious injury.  The same group of twelve slides served as visual aids for both stories.  The second group’s memory of their story, when later tested, was far better and more specific than that of the first group.  A third group of subjects were then given propranolol and told the intensely emotional story with visual aids.  The results of their memory tests were very similar to the first group that tried to recall the dull story.  “Subjects remembered the story, but without any emotional depth” (5).  Another, perhaps even more telling study was done in 2001 by Dr. Pitman.  Forty-one trauma patients in the Massachusetts General Hospital were randomly prescribed ten days’ worth of propranolol or a placebo within six hours of their injuries – mostly car accidents.  After one month, the patients who remained with the study were evaluated.  The difference between the scores of the two groups “was not statistically significant” (3), but only two out of eleven of the propranolol patients were diagnosed with full blown PTSD, where as six out of twenty of the placebo patients were found to have developed it.  Three months later, remaining participants “listened to their own taped verbal descriptions of the trauma and then imagined the event for 30 seconds”.  Six out of fourteen of the placebo patients responded physiologically to reviewing the experience, but none of the propranolol patients were affected.  These results show that receiving beta-blockers after a traumatic experience does make a difference in the “psychophysiological response to trauma” (3).

            There are clear therapeutic possibilities, but is such dampening of emotion really a good or ethical idea?  Hypertension patients have been experiencing the memory altering effects of propranolol without significant complaint (4).  David Speigel, Stanford psychology professor, states that “the real task is to refind yourself in the wake of the trauma, not pretend it did not happen” (4).  Beta-blockers like propranolol are not strong enough to erase a disturbing memory, only to neutralize it.  Whether a person chooses to hold onto the memory or try to ignore it is his or her own decision.  There are other specific practical concerns as well.  How would the distancing and potential blurring influence of propranolol affect the testimony of a rape victim, or his or her ability to identify the guilty party? (1).  While one of the largest needs for and opportunities to treat PTSD is among the men and women of the military, some officials have misgivings about the extended impact that a beta-blocker would have on a soldier in a war zone.  Propranolol prevents the patient from receiving the effects of adrenaline, thus some generals worry that this would remove a soldier’s will to fight (2).  There is also a risk of desensitization to horrible things – “falsifying our perception and understanding of the world.  It risks making shameful acts seem less shameful, or terrible acts less terrible, than they really are” (5).  In that statement and others, the President’s Council on Bioethics has cast its vote in the negative, being very wary of the repercussions and implications of the use of memory altering drugs.  They emphasize two main points: the value of such memories, and the risk of losing one’s humanity.  “Emotional memories, however painful, serve a purpose.  We remember memories linked to emotions longer and better because they help us learn, adapt, survive” (5).  Trying to take a fast track to recovery would disrupt the normal psychological process and perhaps lessen the human sense of empathy, and “diminish our character or our personal development” (5).  On the other hand, scholars like Dr. Pitman postulate that “most people who have PTSD are so debilitated, they would prefer to have their memories tinkered with” (1).  Others say that they do not want to let speculation or legal concerns prevent them from helping a suffering patient.     

            Personally, I am torn on the issue, and have an understanding of both arguments.  I place an extraordinarily high value on memories, in relation to my own concept of self, life, happiness, perspective and wisdom, as well as to my interest in history and its continued relevance.  I agree with President’s Council member Dr. William B. Hurlbut’s statement that “the pattern of our personality is like a Persian rug.  It is built one knot at a time, each woven into the others.  There’s a continuity to self, a sense that who we are is based upon solid, reliable experience” (5).  I believe that your memories are the only things that are truly yours.  They shape how you view the world, and define who you are as a sum of all of your choices, actions, thoughts, behavior, and values.  I also ascribe to the idea that what doesn’t kill you makes you stronger.  All of these things would lead me to say that I would never wish to diminish any of my memories. 

However, my situation is not that clearly cut.  Between the ages of one and a half and six I had to go through a series of painful and traumatic medical tests, as well as a kidney operation when I was five and a half.  I still carry the physical scars, and battle with the emotional and mental ones fourteen years later.  The memories still inspire irrational fear and a sense of revulsion that can mentally incapacitate me for a period of time if I am not able to drive them out fast enough, and can be sparked by hearing a phrase or catching sight of any of a wide range of objects.  Rather than feeling detached from others, I have an extreme sense of empathy, but I do have to deal with friends and loved ones asking why I’m so “psychotic” about my scars.  I went to therapy after the procedure, and have gotten over several related fears, but the deepest, most central fear persists.  I haven’t been tested for it, but I can understand the hardships endured by those who’ve been diagnosed with full blown PTSD. 

My life, like theirs, would be much easier without the chronic sting of memories that you wish would stay dormant in the farthest part of your mind.  Despite my feeling that working through the fears, and living with the memory has made me stronger and contributed greatly to who I am, my most frequent method of dealing with the physical scars is to pretend that they aren’t there and hope that I am not reminded.  That being said, I am tempted to wish a drug like propranolol had been available when those memories were being made.  There have been many times when I’ve wished for the soothing waters of the Lethe, but when I regain my senses I take it back, and determine that the relief is not worth the potential changes to my Self.  I continue to be of that opinion, but it will always be a somewhat unstable one.

Sources:

1. http://www.harvardmagazine.com/on-line/070467.html “Cushioning Hard Memories” an article on PTSD and propranolol.

2. http://www.hno.harvard.edu/gazette/2004/03.18/01-ptsd.html “Pill to calm traumatic memories: Puts the mind’s storehouse in order” an article on PTSD and propranolol.

3. http://www.neuropsychiatryreview.com/march02/ptsd.html “Can Beta Blockers Prevent PTSD? A First Look” another article on PTSD and propranolol.

4. http://daily.stanford.edu/article/2004/4/15/whatIfYouCouldEraseYourMemory “What id you could erase your memory?” an article focusing on the controversy.

5. http://www.cognitiveliberty.org/neuro/memory_drugs_sd.html “Blanks for the memories: Someday you may be able to take a pill to forget painful recollections” a thorough and interesting article from the San Diego Union Tribune.

6. http://webspace.ship.edu/cgboer/limbicsystem.html “The Emotional Nervous System” an explanation of the Limbic and Autonomic Nervous systems.

7. http://www.psych.nyu.edu/phelpslab/papers/interactions%20of%20the%20amygdala04.pdf “Human emotion and memory: interactions of the amygdala and hippocampal complex” a very interesting article on the formation of memory.