A phobia is a type of anxiety disorder, and is defined as an intense, irrational fear of a particular situation, object, animal or activity. People who suffer from a phobia may experience extreme emotional and physical reactions when encountering their particular fear. Nearly everyone fears something. Some people become anxious during thunderstorms. Others get queasy in tall buildings. Still others find themselves jumping onto a chair at the sight of a tiny mouse. But there's a big difference between temporary anxiety that's experienced occasionally and the often crippling, uncontrollable fear that can result in a person going to great lengths to avoid their phobia - even if it means missing a job interview, vacation or school play. When people with phobias can't avoid what they're afraid of, they may experience various symptoms, such as a rapid heartbeat, dizziness, shortness of breath, excessive sweating, trembling or weakness. Most people with phobias realize their fear is excessive and irrational. But they typically are unable to overcome their feelings of dread and the often desperate need to escape the subject of their phobia. Ultimately, this may interfere with the ability to function in daily life. The American Psychiatric Association divides phobias into three main categories including Specific Phobias, Social Phobia - also known as Social Anxiety Disorder -- and Agoraphobia. Specific Phobias, also known as Simple Phobias, are the irrational fear of a very specific situation, place, animal or object. The most common specific phobia is fear of animals such as dogs, cats, mice, snakes or spiders. And that's ONLY the tip of the iceberg. The "Phobias List" identifies more than 500 Specific Phobias, ranging from fear of garlic, dust, clocks and comets, to dancing, snow, strings and puppets. A person with social phobia may be intensely fearful of being singled out, talking to strangers, ridicule, eating or showing embarrassment in social situations. The most common social phobia is fear of public speaking. Agoraphobia is a fear of any situation where it may be difficult to escape or get help if needed. People with agoraphobia often feel unsafe in any public place and may become so disabled by their fear that they become housebound. Phobias typically develop early in life. They may be triggered by experiences, but also tend to run in families. So children whose parents have a phobia are about three times as likely to develop a similar phobia, than where there is no family history. Phobias are the most common anxiety disorder among women overall, and the second-most common anxiety disorder among men over 25. For people who suffer from a phobia, the effects can be life altering. Their lives are often planned around avoiding, concealing or defending their phobia, while struggling to cope with their fear. Most phobias can be successfully treated. If you - or someone you know - is affected by phobias, consult a mental health professional.