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The science behind fear

The science behind fear

Around 25% of all people experience an anxiety disorder in their lifetime.

4 minutes
16 December 2019

Around 25% of all people experience an anxiety disorder in their lifetime. This can be an animal phobia – like being afraid of spiders –, claustrophobia, social anxiety, or a posttraumatic stress disorder. But why is it that someone who is bitten by one dog is suddenly afraid of all dogs? The clinical psychologists of KU Leuven are researching how healthy fear can turn into a clinical anxiety that interferes with your daily life.

Fear in itself is not abnormal: it helps avert danger and negative situations. It becomes a problem when anxiety starts to interfere with your everyday life. “If you’re bitten by the neighbour's aggressive dog, it’s normal to be somewhat scared when you see that dog again. But if you’re too afraid to walk anywhere anymore because you’ve become afraid of all dogs, we consider it an anxiety disorder. If you start avoiding things in your life due to this fear, it impacts your wellbeing, your family and friends, your job,... Anxiety disorders have a high social cost”, explains Professor Dirk Hermans of the Centre for Psychology of Learning and Experimental Psychopathology.

The fact that such a problematic fear can develop is in part due to a phenomenon called generalisation. “This means that your fear expands: you don’t just become scared of the original source of your fear, but of a number of other, similar things as well. For instance: you wash your hands because you’ve just held a can of herbicide and you’re afraid of contamination. That's not unusual, but it becomes problematic if, after a while, you start compulsively washing your hands because your fear is no longer limited to that specific product and you’ve become afraid of cleaning products or paint. It has nothing to do with how intense your fear originally was, but with how this fear is spreading.”


The fact that a fear generalises doesn't have to be a problem in itself: “Fear can extinguish itself again, sometimes even very quickly. That's what we call extinction. It's possible that you’ve become fearful in planes after a turbulent flight. But if you try again, you usually see that it’s not so bad after all. You learn that it doesn't always have to turn out badly. This is also linked to another mechanism: avoidance. Avoiding certain situations more often will reduce the positive relearning experiences. The higher the avoidance, the less extinction and the more generalisation. These three phenomena are interlinked. That's the problem for people with anxiety disorders.”

The good news is that an anxiety disorder is based on learning processes. And what can be learned, is usually reversible. “If you have an experiment where you give a test person a light electric shock each time he/she sees a circle, this test person learns to be afraid of the circle. But if you show them circles later on without this shock, their fear will usually quickly subside. That's exactly what happens with extinction. And this immediately brings us to a treatment: exposing and facing the source of your fear can show you that this fear is no longer needed.”

Road to recovery

You don't have to keep living with an anxiety disorder: “Most anxiety disorders don't spontaneously disappear; patients often need therapy. But not everyone is as quick to seek and find help. Did you know that, on average, patients live with an anxiety disorder for ten years before they have a first treatment session? That’s a long time when you know how easy it can sometimes be to help them.”

In some cases, you only need a few hours to treat an anxiety disorder. “If you have a phobia of something very specific – needles or animals, for instance – this can usually be treated quite easily and effectively. But more complex anxiety disorder frequently also have relatively short treatment periods (for instance ten to twelve sessions). An important part of all these treatments is exposure to what you’re afraid of. If you’re afraid of spiders, you will first look at pictures of spiders and later real spiders, after which you will also touch them.”

“Thanks to our research, we now also better understand how anxiety disorders develop and we can even aim for prevention instead of treatment. This is important for risk groups that will face terrifying situations from time to time, such as fire-fighters, police officers or soldiers. We can provide them with methods and tools to prevent a generalisation of fear. Prevention of anxiety disorders has become much more important.”