 | Post-traumatic stress disorder (PTSD) is an anxiety disorder that some people develop after seeing or living through an event that caused or threatened serious harm or death. Symptoms include flashbacks or bad dreams, emotional numbness, intense guilt or worry, angry outbursts, feeling “on edge,” or avoiding thoughts and situations that remind them of the trauma. |
Currently, many scientists are focusing on genes that play a role in creating fear memories. Understanding how fear memories are created may help to refine or find new interventions for reducing the symptoms of PTSD. For example, PTSD researchers have pinpointed genes that make:
Stathmin, a protein needed to form fear memories. In one study, mice that did not make stathmin were less likely than normal mice to “freeze,” a natural, protective response to danger, after being exposed to a fearful experience. They also showed less innate fear by exploring open spaces more willingly than normal mice.
GRP (gastrin-releasing peptide), a signaling chemical in the brain released during emotional events. In mice, GRP seems to help control the fear response, and lack of GRP may lead to the creation of greater and more lasting memories of fear.
Researchers have also found a version of the 5-HTTLPR gene, which controls levels of serotonin — a brain chemical related to mood-that appears to fuel the fear response. Like other mental disorders, it is likely that many genes with small effects are at work in PTSD.
Studying parts of the brain involved in dealing with fear and stress also helps researchers to better understand possible causes of PTSD. One such brain structure is the amygdala, known for its role in emotion, learning, and memory. The amygdala appears to be active in fear acquisition, or learning to fear an event (such as touching a hot stove), as well as in the early stages of fear extinction, or learning not to fear.
Storing extinction memories and dampening the original fear response appears to involve the prefrontal cortex (PFC) area of the brain, involved in tasks such as decision-making, problem-solving, and judgment. Certain areas of the PFC play slightly different roles. For example, when it deems a source of stress controllable, the medial PFC suppresses the amygdala an alarm center deep in the brainstem and controls the stress response. The ventromedial PFC helps sustain long-term extinction of fearful memories, and the size of this brain area may affect its ability to do so.
"Is an extra-factual memory that convincing?" Quail
asked. "More than the real thing, sir. Had you really gone to Mars
as an Interplan agent, you would by now have forgotten a
great deal; our analysis of true-mem systemsauthentic rec-
ollections of major events in a person's lifeshows that a
variety of details are very quickly lost to the person. Forever.
Part of the package we offer you is such deep implantation of
recall that nothing is forgotten. The packet which is fed to
you while you're comatose is the creation of trained experts,
men who have spent years on Mars; in every case we verify
details down to the last iota. And you've picked a rather easy
extra-factual system; had you picked Pluto or wanted to be
Emperor of the Inner Planet Alliance we'd have much more
difficulty . . . and the charges would be considerably greater."
Reaching into his coat for his wallet, Quail said, "Okay. It's
been my life-long ambition and I can see I'll never really do
it. So I guess I'll have to settle for this."
"Don't think of it that way," McClane said severely.
"You're not accepting second-best. The actual memory, with
all its vagueness, omissions and ellipses, not to say distortions
that's second-best." He accepted the money and pressed a
button on his desk. "All right, Mr. Quail," he said, as the door
of his office opened and two burly men swiftly entered.
"You're on your way to Mars as a secret agent."
- - - Philip K. Dick, We Can Remember it for You Wholesale
Cognitive behavioral therapy (CBT) teaches different ways of thinking and reacting to the frightening events that trigger PTSD symptoms and can help bring those symptoms under control. There are several types of CBT, including
exposure therapy — uses mental imagery, writing, or visiting the scene of a trauma to help survivors face and gain control of overwhelming fear and distress
cognitive restructuring — encourages survivors to talk about upsetting (often incorrect) thoughts about the trauma, question those thoughts, and
In a small study, NIMH researchers recently found that for people already taking a bedtime dose of the medication prazosin (Minipress), adding a daytime dose helped to reduce overall PTSD symptom severity, as well as stressful responses to trauma reminders.
Another medication of interest is D-cycloserine (Seromycin), which boosts the activity of a brain chemical called NMDA, which is needed for fear extinction. In a study of 28 people with a fear of heights, scientists found that those treated with D-cycloserine before exposure therapy showed reduced fear during the therapy sessions compared to those who did not receive the drug. Researchers are currently studying the effects of using D-cycloserine with therapy to treat PTSD.
| Propranolol (Inderal), a type of medicine called a beta-blocker, is also being studied to see if it may help reduce stress following a traumatic event and interrupt the creation of fearful memories. |  |
Propranolol (INN) (IPA: [proˈprænəloʊl]) is a non-selective beta blocker mainly used in the treatment of hypertension. It was the first successful beta blocker developed. Propranolol is commonly marketed by Wyeth under the trade name Inderal.
Scottish scientist James W. Black successfully developed propranolol in the late 1950s. He was awarded the Nobel Prize in Medicine for this discovery in 1988.
Propranolol developed from the early β-adrenergic antagonists dichloroisoprenaline and pronethalol. The key structural modification, which was carried through to essentially all subsequent beta blockers, was the insertion of an oxymethylene bridge into the arylethanolamine structure of pronethalol thus greatly increasing the potency of the compound. This also apparently eliminated the carcinogenicity found with pronethalol in animal models.
 | Curbing Post-Traumatic Stress Disorder with a Pill Dr. Margaret Altemus, an associate professor of psychiatry at Weill Cornell Medical College and an associate attending psychiatrist at NewYork-Presbyterian Hospital/Weill Cornell Medical Center, |
When a person with PTSD recalls a traumatic memory, the body releases a surge of adrenaline which causes an overwhelming sense of emotion – typically, fear, anxiety, and helplessness. From here, Dr. Altemus and colleagues suspect that the traumatic memory and the current emotional experience mingle and "reconsolidate" into a memory even more strongly linked to the sense of fear and helplessness. And, as episodes build upon themselves, the patient's illness intensifies.
Dr. Altemus theorizes that if propranolol is taken immediately after a memory is recalled, it will block adrenaline from reaching receptors in the brain and break the reconsolidation cycle linking the traumatic memory to the recurrence of fear and helplessness. The reconsolidation process will be weakened, and allow the person's fear reaction to the memory to increasingly diminish instead of intensify.
"We do not expect to mimic Hollywood’s ‘Eternal Sunshine of the Spotless Mind,'" says Dr. Altemus. "Instead, we hope that participants with PTSD will remember the details of the trauma, but will no longer be paralyzed by intense fear or helplessness each time the memory is recalled."
This is the first trial, based on the theory of reconsolidation, which is investigating if PTSD can be treated with propranolol. Other investigators have had some success preventing PTSD by treating accident victims with propranolol for the first 10 days after an accident.
References:
- Common drug, given promptly, reduces incidence of post-traumatic stress disorder
- Curbing Post-Traumatic Stress Disorder with a Pill
- WE CAN REMEMBER IT FOR YOU WHOLESALE
- Post Traumatic Stress Disorder Research Fact Sheet
- Propranolol From Wikipedia, the free encyclopedia
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