Drugs That Affect a Lie Detector Test

A lie detector test measures and records physiological changes in the body. When lying, heart rate may increase, and you may fidget or squirm. Some medications, however, can affect lie detector tests.

How Do Polygraph Tests Work?

The New England Journal of Medicine states that lie detector or polygraph tests record the changes in the autonomic nervous system, such as blood pressure, pulse, breathing patterns and perspiration, that occur when the test subject is lying.

Hypertension Medications

Blood pressure medications affect lie detector tests more than any other drug. They lower blood pressure, thus inhibiting changes in blood pressure that would normally occur when the subject is lying.

Benzodiazepines

Benzodiazepines, sedatives used to treat anxiety, are oftentimes taken in an effort to "beat" a lie detector test. However, an examiner can usually detect these drugs in the pretest phase.

Detection

Lie detector examiners are specially trained to decipher and analyze if the test subject is under the influence of medication. During the pretest phase, examiners calculate reaction times and responses to obvious questions.

Controversy

There is great controversy surrounding lie detector tests and their actual ability to determine if someone is lying. Consequently, The New England Journal of Medicine says, "Most state and federal courts restrict the use of polygraph test results or do not allow their use."

References

• The Polygraph Test
• Do Drugs Mask a Polygraph Test?
• Scientific Validity of Lie Detector Tests