A true phobia can have a crippling effect on someone's life - a fear of flying can stop people exploring the world or a fear of open spaces can confine someone as a prisoner in their own home.
Scientists at the University of Queensland believe they might have found a way to silence these types of thoughts.
Their research targets the genes associated with fear-related memories.
Dr Timothy Bredy, senior research fellow at the university's Queensland Brain Institute (QBI), said: "Rather than being static, the way genes function is incredibly dynamic and can be altered by our daily life experiences, with emotionally relevant events having a pronounced impact."
The technique could be especially helpful to those suffering from post-traumatic stress disorder (PTSD) by controlling the response associated with traumatic memories.
PTSD and similar disorders occur due to impairments in "rapid behavioural adaptation" when someone undergoes a stressful event.
Fear extinction can be brought about by a process of gene regulation causing an "inhibitory learning process" when the initial response is no longer needed.
Xiang Li, a PhD candidate and the study's lead author, said: "What is most exciting is that we have revealed an epigenetic state that appears to be quite specific for fear extinction."