Scientists are using their growing knowledge of brain chemicals -- and the role they play in saving and accessing memories -- to find ways to help people coping with one symptom of PTSD: the painful replay of traumatic memories. We'll review today's Chicago Tribune article, Drug Eases Pain of Bad Memories, to get an update on progress in this somewhat controversial area; and we'll take a look at results of studies conducted by the National Institute of Mental Health on the role the brain plays in PTSD.

 
From the Chicago Tribune:

There is no definitive treatment for PTSD and no cure, and the number of cases is only expected to grow as a result of U.S. military action overseas. This week, published research found that 12 percent of soldiers returning from Iraq were diagnosed with post-traumatic stress disorder, depression or another serious mental illness. Brain scientists think they have found a way to help by using a drug called propranolol to alter traumatic thoughts. It appears that the drug, a beta blocker used to treat high blood pressure, interferes with stress hormones in the brain to defuse the impact of horrific memories.

While use of the drug for this purpose has not been approved, some psychiatrists already have begun to prescribe it to patients with PTSD. (Other beta blockers do not seem to affect the brain the same way.) Researchers emphasize that the drug can lower the intensity of a bad memory--but not erase it. "It's not that people will no longer remember the trauma, but the memory will be less painful," said Alain Brunet, a psychologist at McGill University in Montreal, where experiments on human subjects are under way.

An interesting part of the new research and findings is that it's been a century's old scientific view that memories are fluid only for a matter of a few hours (the article says 6), and then following that period of time become fixed. They're stored in the fixed state, and can't be changed in any way in the future.

But Karim Nader, a pioneering McGill psychologist, was able to show that long-term memories aren't nearly as hardwired as scientists had thought. When we retrieve a memory, Nader found, it again enters a vulnerable state where it could be manipulated or even lost. "It was formerly thought that once a memory is fixed you can't mess around with it," said Nader. "That was scientific dogma for 100 years." The brain's wiring changes each time something goes into long-term memory, but not all memories are equal, he said. "You remember the day of your wedding better than three Tuesdays ago when there was nothing important going on."

Emotional memories, Nader explained, activate a second process that ups their intensity. This is called a "gain switch" and can be thought of as the volume control on a radio. Studies have shown that emotionally arousing events cause stress-related hormones such as adrenaline to be released by the brain's amygdala, which is involved in emotional learning and memory. PTSD may develop when the event is so emotionally powerful, and so much adrenaline is released, that the "gain switch" is set too high.

As the National Institute for Mental Health (NIMH) explains:

NIMH and the VA sponsor a wide range of basic, clinical, and genetic studies of PTSD. … Studies in animals and humans have focused on pinpointing the specific brain areas and circuits involved in anxiety and fear, which are important for understanding anxiety disorders such as PTSD. Fear, an emotion that evolved to deal with danger, causes an automatic, rapid protective response in many systems of the body.

It has been found that the body's fear response is coordinated by a small structure deep inside the brain, called the amygdala. The amygdala, although relatively small, is a very complicated structure, and recent research suggests that different anxiety disorders may be associated with abnormal activation of the amygdala.

What appears to happen each time a memory is retrieved by the brain is that the amygdala releases more hormones, the painful memories being all the more intensified with each recall. This is where the drug propranolol comes to the rescue; it has been shown in lab experiments to desensitize the subject of expected fear-producing memories.

Trials are now underway on men and women and seem to reflect the results of lab research showing that those taking the blood pressure pill propranolol have a milder reaction to traumatic memories than those taking a placebo. Additionally, propranolol may help to ease the painful memories immediately after a traumatic incident, the Chicago Tribune explains:

Dr. Roger Pitman, a professor of psychiatry at Harvard Medical School, wondered if giving propranolol as soon as possible after a traumatic event could prevent indelible, terrifying memories from taking hold. He tested the idea on 41 people who had experienced car accidents, assaults and other events that brought them to a Massachusetts emergency room. They received the drug within six hours of their mishaps. The results were dramatic.

Three months later, 22 of the victims listened to audiotapes on which they had described their traumas. None of those who took propranolol showed strong responses to the tapes, but eight of the placebo patients were obviously shaken by reliving their experiences. Their heart rates increased, their palms sweated, their muscles twitched--all signs of PTSD. Now Pitman's group is pursuing a study in which patients with chronic PTSD are treated repeatedly with propanolol. "If we get positive results, there are many potential applications for people with PTSD from a variety of sources, including Hurricane Katrina and the Iraq War," Pitman said.

These treatments are not without controversy as some ethicists are concerned that by trying to numb the pain we may be setting ourselves up to be less capable of handling psychological pain in the future. But the brain researchers counter back:

"Many people have thought of these as amnesia drugs: `I would like to get rid of the memory of a horrible experience I had with another person; I'll just take propranolol and get rid of it,'" said James McGaugh, a neurobiologist at the University of California at Irvine whose work on learning and memory paved the way for research by Pitman and others. "Well, propranolol does not remove memories."

The day after Nader's first study was published, a woman called and asked whether she could have the memories of her abusive first husband erased. "The idea of erasing memory is just silly," Nader said. "We can't do it; nor do we want to. But if we can turn down the intensity of the memory sufficiently that these patients can respond to traditional treatments, that's the goal, I think."

Be sure to read the whole Chicago Tribune piece, and visit the NIMH website if you'd like to learn more on this issue -- and PTSD in general. And visit PTSD Combat for the latest PTSD resources, news, research, and veterans events.