Polygraph Knoxville

As a provider of Polygraph in Knoxville, one of the questions we get asked most frequently is whether or not mental illnesses such as depression, anxiety, bipolar, ADHD, and PTSD can affect the outcome or the accuracy of a polygraph examination. With around forty million adults in the United States diagnosed with anxiety-related disorders, it is easy to see why it is such a common question! The short answer is that as long as your condition is stable, then it should not mean that you cannot accurately take a polygraph in Knoxville. Let’s take a closer look at why.

How Does a Polygraph Work?

In order to understand why most controlled mental illnesses are not going to impact your ability to take a polygraph in Knoxville, we first need an understanding of how a polygraph exam actually works. Polygraph machines help to uncover lies by measuring physiological responses. When human beings are untruthful, our bodies react by increasing our heart rate and blood pressure and producing more sweat. Depending on the type of polygraph equipment being used, between four and six sensors are attached to the subject to measure physiological responses, including:

  • Breathing Rate
  • Pulse
  • Blood Pressure
  • Perspiration

What Does This Mean For People with Mental Illness?

This means that as long as your condition is reasonably well controlled and you are still able to sit relatively still, breathe normally, and follow instructions, there should be no issue in administering a polygraph in Knoxville. If you are taking medication to aid in managing these conditions, it is important to make your examiner aware of this prior to taking a polygraph in Knoxville. It will not disqualify you from taking the test, but it may make changes in heart rate and blood pressure more difficult to spot, so your examiner will want to know in order to make appropriate allowances for your medication. You should take it as you usually would on the day of your polygraph exam. An experienced polygraph examiner is able to calibrate the test to accurately account for this type of medication by asking a series of dummy questions to produce baseline results.

Are There Any Medical Conditions That Can Affect a Polygraph?

While most of the common mental illnesses like anxiety and depression will have little to no impact on the results of a polygraph in Knoxville, there are some conditions that could affect the results. If the subject has a severe mental health condition involving paranoia or delusions, such as schizophrenia, then the test results may be inaccurate. Any condition that substantially alters someone’s perception is going to produce an abnormality in the results. An experienced provider of polygraph in Knoxville should understand that these conditions could impact the test and may choose to refuse the test on ethical conduct. It is better to decline the test than have an innocent person potentially fail, or a guilty one pass, because of their medical condition.

Choosing the Right Polygraph Examiner

One of the most important things to take into account when booking a polygraph in Knoxville is deciding which polygraph examiner you will use. A polygraph exam is only as credible as the examiner conducting it. The more experienced your examiner is, the more accurate your polygraph results are likely to be. That is especially important if you are someone who suffers from anxiety, depression, or another mental health issue. As mentioned above, you need an experienced polygraph expert to be able to make the necessary adjustments to account for any medication you might be taking to manage your condition. Even if you are not suffering from mental health issues, you need to know that your results are accurate when the truth matters.

Kendall Investigations was founded by former Special FBI Agent Ken Shull, one of the leading polygraph experts in the world. In addition to having headed up the FBI’s entire polygraph department for several years, he is also the only person in the world to have attained a Master of Science Degree in Polygraphy. Ken is also a member of the American Polygraph Association and The American Association of Police Polygraphists and has been published in a number of research journals. You may even have seen Ken on television offering expert counsel for such shows as Couples Court with the Cutlers and Chrisley Knows Best! In short, when it comes to qualifications and experience, you will not find someone more qualified to perform a polygraph in Knoxville or the rest of the country. Whether you need to prove your innocence in a criminal case, repair a relationship following claims of infidelity, or even support your application for specific jobs, Kendall Investigations can provide you with an accurate polygraph exam that will help to uncover the truth.

Uncover the truth!


Ken Shull served as a Special Agent with the FBI for almost 25 years and was head of the FBI Polygraph program until his retirement in 2001. At that time he set up the Kendall Investigations practice as a private investigator in Knoxville, TN offering Polygraph services, private investigations, and security guards. Ken is a member of the American Polygraph Association and The American Association of Police Polygraphists.

The Truth is Still the Truth Even if No One Believes it, A Lie is Still a Lie Even if Everyone Believes it.