Phobias usually develop during childhood, adolescence or early adulthood following a frightening event or a stressful situation. However, it is not always clear why some phobias occur.
Simple phobias usually develop in early childhood, often between the ages of four and eight. A simple phobia can sometimes be traced to an early childhood experience. For example, if a young child is trapped in a confined space, they may develop a fear of enclosed spaces (claustrophobia) when they are older.
If someone shares the same phobia with another family member, such as a fear of spiders (arachnophobia), they may have learned to fear spiders as a child, rather than the phobia being passed on genetically (running in families).
The exact causes of complex phobias, such as agoraphobia and social phobia, are unknown. However, it is thought that genetics, brain chemistry and life experiences may all play a part in the development of these phobias.
Social phobias may be caused by a previous intense or anxious experience in a social situation. Alternatively, a person's social confidence may not have had the chance to fully develop past the normal stage of shyness experienced as a young child