In humans, doctors prescribe tranquilizers to treat a variety of anxiety disorders, which work much the same way as the lidocaine in goldfish, McEwen said.
"They have the classic calming down effect," he said. "But why would you want to suppress fear in the first place. It's fear that prevents us from doing crazy things. One can argue that psychopaths don't have fear of consequences."
Drugs like benzodiazepines can be addictive and hard to "wean off," McEwen said.
"There are no easy solutions," he said. "The message is we would not always want to give a pill because often these systems are involved in doing good things."
Scientists have only tapped the "tip of the iceberg" when it comes to understanding these disorders, according to McEwen, but they do suspect a combination of genetic factors and life experiences.
"Good science has been done on how important the environment is," he said. "Adverse events in childhood can have terribly adverse consequences."
Parents can sometimes transmit those anxieties to their children.
"The spookiest part is that studies of Holocaust survivors showed the children had the same symptoms as their parents," McEwen said. "How is that passed on?"
Therapist Resneck-Sannes uses behavioral therapy to help her patients through their most frightening phobias.
"One woman is terrified of the MRI, even the open one, so I started to go through her history and get some understanding of how it happened and started looking at her defensive responses," she said.
Resneck-Sannes said she is teaching the woman to slow her breathing and heart rate and to imagine scenarios when she is not angst-ridden.
"There is an arousal system in the body and what the body wants to do is escape," she said. "It depends on the disorder, but we use a combination of thinking thoughts and calming the arousal in the body so they can feel like they have some control."
But new research on rats and humans may open even more doors to helping those with fears.
Elizabeth Phelps, a professor of psychology at New York University, questioned whether the Japanese goldfish research would have any applicability to humans, whose fear center is based in the amygdala in the temporal lobe, not the cerebellum, where it is in the fish.
She has been doing pionering research on the amygdala , a region of the brain located deep within the medial temporal lobes, a part of the limbic system that controls emotions.
NYU scientists have already discovered that they can inject drugs into the amygdalas of rats to prevent re-storage of memories and effectively erase them.
Such interventions are not safe in humans, say researchers, but they have learned much about how new brain memories are stored.
"These brain regions are important in the expression of that memory," Phelps said. "It's not what you tell me you remember. Memory is more than that. It's how to ride a bike or the anxiety when you encounter something that was dangerous before. It's a big component of what is so traumatic, the pathological aspect of memory."