Trypanophobia

Fear of needles, known in medical literature as needle phobia, is the extreme fear of medical procedures involving injections or hypodermic needles.

It is occasionally referred to as aichmophobia, belonephobia, or enetophobia, although these terms may also refer to a more general fear of sharply pointed objects. It has also been referred to as trypanophobia, although the origin and proper usage of that term is highly controversial.

The condition was officially recognized in 1994 in the DSM-IV (Diagnostic and Statistical Manual, 4th edition) as a specific phobia of blood/injection/injury type. Phobic level responses to injections cause sufferers to avoid inoculations, blood tests, and in the more severe cases, all medical care.

It is estimated that at least 10% of American adults have a fear of needles, and it is likely that the actual number is larger, as the most severe cases are never documented due to the tendency of the sufferer to avoid all medical treatment.

According to Dr. James G. Hamilton, author of the pioneering paper on needle phobia, it is likely that the form of needle phobia that is genetic has some basis in evolution, given that thousands of years ago humans who meticulously avoided stab wounds and other incidences of pierced flesh would have a greater chance of .

The discussion of the evolutionary basis of needle phobia in Hamilton's review article concerns the vasovagal type of needle phobia, which is a sub-type of blood-injection-injury phobia. This type of needle phobia is uniquely characterized by a two-phase vasovagal response. First, there is a brief acceleration of heart rate and blood pressure. This is followed by a rapid plunge in both heart rate and blood pressure, sometimes leading to unconsciousness. The loss of consciousness is sometimes accompanied by convulsions and numerous rapid changes in the levels of many different hormones.

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