SCIENTISTS have discovered how to turn off a fear switch in the brain, a study shows.
The breakthrough could lead to new treatments for patients with post-traumatic stress disorder (PTSD), US researchers said.
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Researchers found that changes in the brain can lead to a state of generalised fear, when a person’s fear response kicks in even in the absence of a real threat.
Taking the common 5p antidepressant fluoxetine — also known as Prozac — immediately after a fright helped avoid this state of generalised fear longer term, they found.
Professor Nick Spitzer, of the University of California San Diego, said: “Our results provide important insights into the mechanisms involved in fear generalisation.
“The benefit of understanding these processes at this level of molecular detail — what is going on and where it’s going on — allows an intervention that is specific to the mechanism that drives related disorders.
“Now that we have a handle on the core of the mechanism by which stress-induced fear happens and the circuitry that implements this fear, interventions can be targeted and specific.”
PTSD is an anxiety disorder that is caused by very stressful, frightening or distressing events and can result in nightmares, flashbacks and feelings of isolation.
It affects around one in 10 Brits at some point in their life — around 6.7million people.
Causes can range from serious road accidents to violent assaults, health problems or issues in childbirth.
Treatments can involve talking therapies, like cognitive behavioural therapy, and antidepressants like paroxetine or sertraline.
The latest study, published in Science, looked at the brains of mice to see how neurotransmitters in the brain affect generalised fear.
They found putting the mice under stress caused the chemical signals in the brain cells to change, producing the generalised fear response.
Researchers found the same change in brain cells in the brains of dead PTSD patients.
PROMISING TREATMENT
When mice were treated with fluoxetine immediately after a stressful event, the change did not occur.
But researchers said the drug had no effect after the change occurs, which is why antidepressants do not work for all PTSD patients.
They said the findings are a promising start down a path that could lead to more effective treatments.
What are the symptoms of post-traumatic stress disorder (PTSD)?
Re-experiencing is the most typical symptom of PTSD.
This is when a person involuntarily and vividly relives the traumatic event in the form of:
- flashbacks
- nightmares
- repetitive and distressing images or sensations
- physical sensations, such as pain, sweating, feeling sick or trembling
Some people have constant negative thoughts about their experience, repeatedly asking themselves questions that prevent them coming to terms with the event.
For example, they may wonder why the event happened to them and if they could have done anything to stop it, which can lead to feelings of guilt or shame.
Source: The NHS