Why Do We Have Phobias? How Intense Fears Form and How They Are Treated

A tiny spider appears in the corner of the bathroom, and a grown adult, who knows perfectly well it is harmless, cannot go in. Someone else plans long detours to avoid a bridge, or refuses a vaccine because of the needle. Phobias can seem irrational to others, but they are among the most common mental health conditions in the world, and science understands rather well how they arise.

Fear is useful, phobia is too much

Fear is one of our most important survival tools. When we sense danger, the brain’s alarm system, centred on a region called the amygdala, triggers the fight-or-flight response: the heart races, breathing speeds up, muscles tense.

A phobia is when this alarm goes off too strongly, too often and for the wrong reasons. Psychiatrists speak of a specific phobia when the fear:

• is out of proportion to the actual danger,
• appears almost every time the person meets the feared thing,
• lasts for months,
• leads to avoidance or distress that affects daily life.

According to a 2018 review in The Lancet Psychiatry, specific phobias are among the most common mental disorders: a substantial share of people, roughly one in ten in many surveys, will have one at some point in their lives. They are more common in women and usually begin in childhood.

The most common types

Fear of public places and crowds (agoraphobia) and fear of being judged by others (social anxiety disorder) are related but are classified separately, because they are broader and work somewhat differently.

Why spiders and not cars?

Here is a puzzle. Cars, electrical sockets and cigarettes kill far more people today than spiders or snakes. Yet phobias of spiders, snakes, heights and the dark are common, while phobias of cars are rare. Why?

In 2001, psychologists Arne Öhman and Susan Mineka brought together a large body of evidence for preparedness: evolution has prepared the human brain to learn fears of threats that endangered our ancestors for millions of years. In experiments, people and monkeys learn to fear pictures of snakes and spiders faster than pictures of flowers or mushrooms, and those fears are harder to unlearn. Laboratory-raised monkeys that had never seen a snake quickly developed a fear of snakes after watching other monkeys react with fear, but not of flowers shown in the same way.

In other words, we are not born with phobias, but we are born ready to learn certain fears easily.

How a phobia forms and persists

Psychologists describe several routes into a phobia:

1. A direct bad experience, such as being bitten by a dog or stuck in a lift.
2. Observation: watching a parent scream at a spider can teach a child that spiders are dangerous.
3. Information: frightening stories, warnings or films.

Not everyone who has these experiences develops a phobia. Genes, temperament and stress all play a role.

The key to why a phobia lasts is avoidance. Every time a person avoids the feared thing, they feel instant relief. The brain treats that relief as a reward and concludes: “Good thing we escaped, it really was dangerous.” Because the fear is never tested, the person never learns that nothing bad would have happened. The fear grows, and the circle of avoided places and situations widens.

Exposure therapy: facing the fear step by step

The good news is that specific phobias are among the most treatable mental health problems. A 2008 meta-analysis by Kate Wolitzky-Taylor and colleagues found that exposure-based treatments worked better than other psychological approaches.

In exposure therapy, the person, guided by a therapist, approaches the feared thing gradually, starting with something mildly scary, such as a picture of a spider, and moving up a “fear ladder”. At each step they stay until the anxiety naturally fades. The brain learns something new: “I was close to it and nothing terrible happened.” This new learning gradually overrides the old fear.

Exposure can also be done with virtual reality, which is useful for fears of flying or heights. Some treatments squeeze the whole process into one long session of a few hours, with good results for many people.

When to seek help

Many people live with mild fears without problems. It is worth seeing a professional if a fear makes you avoid important things, such as medical care, travel, work or time with family, or if it causes panic attacks. Treatment is usually short and effective; avoidance, by contrast, tends to make phobias worse over time.

In short

• A phobia is an intense, lasting fear out of proportion to the real danger.
• Specific phobias are very common and usually start in childhood.
• Evolution has prepared us to learn fears of snakes, spiders and heights quickly.
• Phobias can start with a bad experience, observing others or frightening information.
• Avoidance brings relief but keeps the phobia alive.
• Exposure therapy, facing the fear step by step, is the most effective treatment.