A delusion is defined as a state of irrational belief that holds even when there is strong evidence to the contrary. Now, a researcher from the University of Adelaide in Australia believes he can explain why some individuals are unable to escape their delusions, and it is all down to faulty "reality testing."
This is according to a study recently published in the journal Frontiers in Psychology.
Prof. Phillip Gerrans, a philosopher at the University of Adelaide, explains that both delusions and dreams are linked to faulty reality testing in the cognitive regions of the brain.
He says that usually, reality testing in the brain monitors a "story telling" system that triggers a narrative of a person's experience.
"In someone who has problems with reality testing, that story might persist and may even be elaborated and translated into action. Such people can experience immense mental health difficulties, even to the point of becoming a threat to themselves or to others," says Prof. Gerrans.
Familiar and unfamiliar feelings can prompt delusions
In his study, Prof. Gerrans focuses on delusions that can be prompted by feelings of familiarity and unfamiliarity.
The "Capgras delusion" is one example of this, which Prof. Gerrans explains is the delusion of "doubles."
Prof. Gerrans says he believes that some people are unable to break free of their delusions because they have faulty "reality testing" in the cognitive region of the brain.
He writes of a man who experienced a serious head injury. After spending 1 year in the hospital, he returned home to his family. But although he recognized his family's faces, he believed they were impostors.
"His family looked familiar but didn't feel familiar, and the story in his head made sense of that feeling. It didn't matter how much people tried to point out that his family was the same, in his mind they had been completely replaced by impostors," explains Prof. Gerrans.
He then moves on to the "Fregoli delusion." This is when a person believes they are being followed by a familiar person in disguise. Prof. Gerrans explains that this is a way for a person to handle a familiar feeling that is triggered by seeing a stranger.
He says people can experience feelings of unfamiliarity and familiarity in conditions they are more familiar with.
These feelings often occur in déjà vu, which is the feeling that a new place or situation is familiar. Jamais vu can also provoke these feelings. This is when a person feels that a situation that they have been in before is unfamiliar.
"However, such feelings do not lead to delusion in people whose reality testing is intact," says Prof. Gerrans.
Improving outcomes for people with delusions
According to the National Institute of Mental Health, approximately 26.2% of Americans aged 18 and older suffer from some form of mental disorder - many of which include delusions as a symptom.
Prof. Gerrans says that if reality testing is better understood, it could lead to improved outcomes for people who experience delusions.
"Trying to treat someone experiencing these delusions by telling them the truth is not necessarily going to help, so new strategies need to be developed to assist them.
Ultimately, that's the aim of this work - to help explain the nature of reality testing in order to help people find a way of working through or around their delusions so that the delusions no longer adversely affect their lives."
Medical News Today recently reported on a study revealing a clue as to how some people can remember their dreams.