A specific phobia involves an intense, persistent fear of a specific object or situation that's out of proportion to the actual risk. There are many types of phobias, and it's not unusual to experience a specific phobia about more than one object or situation. Specific phobias can also occur along with other types of anxiety disorders.

Common categories of specific phobias are a fear of:

• Situations, such as airplanes, enclosed spaces or going to school
• Nature, such as thunderstorms or heights
• Animals or insects, such as dogs or spiders
• Blood, injection or injury, such as needles, accidents or medical procedures
• Others, such as choking, vomiting, loud noises or clowns

Each specific phobia is referred to by its own term. Examples of more common terms include acrophobia for the fear of heights and claustrophobia for the fear of confined spaces.

No matter what specific phobia you have, it's likely to produce these types of reactions:

• An immediate feeling of intense fear, anxiety and panic when exposed to or even thinking about the source of your fear
• Awareness that your fears are unreasonable or exaggerated but feeling powerless to control them
• Worsening anxiety as the situation or object gets closer to you in time or physical proximity
• Doing everything possible to avoid the object or situation or enduring it with intense anxiety or fear
• Difficulty functioning normally because of your fear
• Physical reactions and sensations, including sweating, rapid heartbeat, tight chest or difficulty breathing
• Feeling nauseated, dizzy or fainting around blood or injuries
• In children, possibly tantrums, clinging, crying, or refusing to leave a parent's side or approach their fear

Much is still unknown about the actual cause of specific phobias. Causes may include:

• Negative experiences. Many phobias develop as a result of having a negative experience or panic attack related to a specific object or situation.
• Genetics and environment. There may be a link between your own specific phobia and the phobia or anxiety of your parents — this could be due to genetics or learned behavior.
• Brain function. Changes in brain functioning also may play a role in developing specific phobias.

These factors may increase your risk of specific phobias:

• Your age. Specific phobias can first appear in childhood, usually by age 10, but can occur later in life.
• Your relatives. If someone in your family has a specific phobia or anxiety, you're more likely to develop it, too. This could be an inherited tendency, or children may learn specific phobias by observing a family member's phobic reaction to an object or a situation.
• Your temperament. Your risk may increase if you're more sensitive, more inhibited or more negative than the norm.
• A negative experience. Experiencing a frightening traumatic event, such as being trapped in an elevator or attacked by an animal, may trigger the development of a specific phobia.
• Learning about negative experiences. Hearing about negative information or experiences, such as plane crashes, can lead to the development of a specific phobia.

Although specific phobias may seem silly to others, they can be devastating to the people who have them, causing problems that affect many aspects of life.

• Social isolation. Avoiding places and things you fear can cause academic, professional and relationship problems. Children with these disorders are at risk of academic problems and loneliness, and they may have trouble with social skills if their behaviors significantly differ from their peers.
• Mood disorders. Many people with specific phobias have depression as well as other anxiety disorders.
• Substance abuse. The stress of living with a severe specific phobia may lead to abuse of drugs or alcohol.
• Suicide. Some individuals with specific phobias may be at risk of suicide.