Phobia is defined as a persistent, irrational, intense fear of a specific object, activity, or situation, that can be recognised as being excessive or unreasonable by the individual.
Specific phobia (sometimes known as simple phobia) is a fear of a well-defined object or situation, for example, fear of spiders or dogs, driving on motorway, crossing bridges, etc.
Social phobia (also known as social anxiety) involves fear and avoidance of people and social situations, usually involving fear of embarrassment and humiliation.
Claustrophobia is a fear of enclosed spaces, where escape may appear to be difficult.
Agoraphobia can be seen as a cluster of phobias related to leaving home, entering shops, being in crowds and public places, or travelling on public transport. Many people with agoraphobia also have a history of panic attacks. They may worry about being in an environment, or situation, from which escape would be difficult.