Millions of Americans live with excessive and debilitating fears that make routine situations and experiences painful. Phobias are complex fears that often stem from stressful childhood situations or severe trauma. Overwhelming fears could once have been used as survival mechanisms in early humans, but many of those programmed fears are useless in our modern culture. The American Psychiatric Association has defined more than 100 different phobias; each one is rooted deeply in the psyche in an unusual way that may require medical intervention. Doctors haven’t found a genetic link to phobias, or full-proof treatments for each one, but patients may find relief with a variety of treatments and therapies.