Can Anxiety or Medication Affect a Polygraph Test?

If you are reading this, there is a good chance you have a polygraph examination approaching and a knot of worry sitting somewhere behind your ribs. Perhaps you take medication for anxiety or depression. Perhaps you have been diagnosed with PTSD, panic disorder or generalised anxiety disorder. Perhaps you simply know yourself to be an anxious person — and the thought of being attached to monitoring equipment while someone asks you direct questions is enough to make your palms sweat before you have even left the house. You want to know: “Will my anxiety make me fail? Will my medication interfere with the results?”

These are among the most common questions we receive at the Centre for Forensic Neuroscience, and they deserve honest, evidence-based answers rather than vague reassurances. The short answer is that ordinary anxiety — even intense anxiety — does not, by itself, cause false results in a properly conducted polygraph examination. But the longer answer matters too, because it explains why that is the case, what role medication plays, how a competent examiner adapts the process, and under what circumstances testing genuinely should not proceed.

Why Everyone Is Nervous — and Why That Is Expected

Let us begin with the most important reassurance: virtually every person who sits for a polygraph examination is nervous. This is not an anomaly. It is a predictable and well-understood feature of the testing situation. You are in an unfamiliar environment, attached to physiological sensors, facing questions about something that matters to you. It would be unusual not to feel anxious.

Professional examiners understand this completely. The polygraph process is not designed to compare your responses against some idealised calm baseline. Instead, the examination methodology — whether using the Comparison Question Test, the Concealed Information Test, or another validated format — is structured to compare your physiological responses to different types of questions within the same examination session. This is a critical distinction.

When a polygraph examination is conducted properly, the examiner is not looking at whether you are “nervous” in absolute terms. They are examining the pattern of your physiological responses — the relative differences between how your body responds to relevant questions (those directly related to the issue under investigation) and comparison questions (carefully constructed control questions designed to elicit a known psychological response). An anxious person produces elevated responses throughout the examination, but the critical diagnostic information lies in the differential pattern between question types, not in the overall level of arousal.

The Difference Between Baseline Anxiety and Deception-Related Responses

This distinction is worth understanding clearly, because it is the reason why general nervousness does not produce false outcomes in competent examinations.

Baseline nervousness is the tonic, generalised arousal you bring into the examination room. Your heart rate may be slightly elevated. Your breathing may be shallow. Your electrodermal activity may be somewhat higher than usual. This arousal is relatively constant — it persists throughout the examination and affects your responses to all questions more or less equally.

Deception-related responses, by contrast, are phasic — they are transient, question-specific physiological changes that occur in response to particular stimuli. When someone provides a deceptive answer to a relevant question, the autonomic nervous system produces a characteristic pattern of changes: a brief suppression of respiratory activity, a measurable increase in electrodermal response, and changes in cardiovascular functioning. These responses are superimposed on top of whatever baseline arousal is already present.

Modern scoring methodologies — including both traditional numerical scoring and computerised algorithm-based analysis — are designed to detect these differential patterns. They are not measuring how nervous you are in general. They are measuring whether specific questions produce significantly different physiological responses compared to other questions. Research consistently demonstrates that general anxiety, while it may make the examination more physically uncomfortable for the examinee, does not systematically bias the outcome towards a deceptive result.

The polygraph does not measure anxiety. It measures the relative patterning of physiological responses across different question types. An anxious truthful person remains distinguishable from a deceptive person because the pattern of their responses differs, even if the overall level of arousal is elevated.

Medication and the Polygraph: What the Evidence Shows

Medication is a legitimate and understandable concern. If you take daily medication for a mental health condition, you may worry that it will somehow mask genuine responses, create false responses, or render the examination invalid. The reality is more nuanced than either “medication has no effect whatsoever” or “medication makes polygraph impossible.”

The key principle is this: most commonly prescribed psychiatric medications, taken at stable therapeutic doses as part of an established treatment regimen, do not prevent a valid polygraph examination from being conducted. However, certain medications can influence physiological reactivity in ways that a competent examiner must be aware of and account for. What matters is disclosure, stability, and professional judgement.

Antidepressants: SSRIs and SNRIs

Selective serotonin reuptake inhibitors (SSRIs) such as sertraline, fluoxetine, citalopram and escitalopram, along with serotonin-noradrenaline reuptake inhibitors (SNRIs) such as venlafaxine and duloxetine, are among the most widely prescribed medications in the UK. They are used to treat depression, generalised anxiety disorder, panic disorder, obsessive-compulsive disorder and, in some cases, post-traumatic stress disorder.

SSRIs and SNRIs can have modest effects on autonomic nervous system functioning. Some individuals experience slight reductions in heart rate variability or subtle changes in electrodermal responsiveness. However, the peer-reviewed literature does not support the proposition that these medications systematically prevent valid polygraph testing. Because the polygraph relies on within-session comparisons — your response to one question relative to another — a consistently dampened autonomic profile does not eliminate the differential patterns that the examination is designed to detect.

The critical consideration is stability. If you have been taking an SSRI or SNRI at a consistent dose for several weeks or months, your autonomic nervous system has adapted to the medication, and your physiological baseline has stabilised. This is the optimal scenario for testing. By contrast, if you have recently started, stopped, or significantly changed the dose of an antidepressant, your physiology may be in a transitional state, which could complicate interpretation. In such cases, it may be advisable to postpone the examination until the new regimen has stabilised.

Benzodiazepines

Benzodiazepines — including diazepam, lorazepam, alprazolam and clonazepam — are a more significant consideration. These medications act on GABA receptors to produce anxiolytic, sedative and muscle-relaxant effects. They directly dampen autonomic nervous system reactivity, which is the very system the polygraph monitors.

At therapeutic doses taken as part of a stable, prescribed regimen, benzodiazepines do not necessarily preclude polygraph testing, but the examiner must be aware of their use and may need to interpret results with appropriate caution. At higher doses, or when taken acutely (for example, taking a benzodiazepine specifically to “calm down” before the test), these medications can suppress physiological reactivity to the point where valid discrimination between question types becomes difficult or impossible.

For this reason, examinees should never take a benzodiazepine that has not been prescribed for them, and should not alter their prescribed dose specifically in anticipation of the examination. If you take a benzodiazepine as part of your regular treatment, you should continue taking it as normal and disclose this to the examiner during the pre-test interview. The examiner will then make an informed assessment of whether the examination can proceed on that occasion.

Beta-Blockers

Beta-adrenergic blockers such as propranolol and atenolol are commonly prescribed for hypertension, cardiac arrhythmias, migraine prophylaxis and, in some cases, performance anxiety. They work by blocking the effects of adrenaline on the cardiovascular system, reducing heart rate and blood pressure.

Because the polygraph monitors cardiovascular activity as one of its primary channels, beta-blockers are relevant to the examination process. They can reduce heart rate reactivity and dampen blood pressure responses to psychological stimuli. However, beta-blockers do not significantly affect electrodermal activity (skin conductance) or respiratory patterns — the other two primary channels of polygraph recording. A competent examiner who is aware that the examinee is taking a beta-blocker can adjust their interpretive weighting accordingly, placing appropriate emphasis on the channels least affected by the medication.

As with other medications, the important thing is to disclose your beta-blocker use honestly during the pre-test interview. Attempting to conceal medication use serves no constructive purpose and could compromise the validity of the examination.

ADHD Medication: Stimulants and Non-Stimulants

Stimulant medications prescribed for ADHD — including methylphenidate (Ritalin, Concerta) and lisdexamfetamine (Elvanse) — increase sympathetic nervous system activity. They can elevate heart rate, increase blood pressure and heighten general physiological arousal. Non-stimulant ADHD medications such as atomoxetine (Strattera) and guanfacine (Intuniv) have different pharmacological profiles and generally produce less pronounced autonomic effects.

Stimulant medication does not invalidate polygraph testing. In fact, because these medications increase overall physiological reactivity, they may actually make differential responses more pronounced rather than less. However, the examiner needs to know about their use so that elevated baseline readings are understood in context rather than misinterpreted.

If you take ADHD medication, you should generally take it at your usual time on the day of the examination. The goal is for you to be in your normal physiological state — the state in which you function most effectively. An examiner who is informed about your medication can account for its effects in their assessment. For a broader discussion of how ADHD and other neurodevelopmental conditions are accommodated, see our detailed article on neurodiversity and polygraph examinations.

Antipsychotics

Antipsychotic medications — both first-generation (typical) and second-generation (atypical) — are prescribed for conditions including schizophrenia, schizoaffective disorder, bipolar disorder, and in some cases severe treatment-resistant depression or anxiety. Examples include quetiapine, risperidone, olanzapine, aripiprazole and haloperidol.

These medications can have significant effects on autonomic nervous system functioning, including reductions in heart rate variability, blood pressure changes, and altered electrodermal activity. Their sedative properties may also affect an individual’s cognitive processing speed, attention and ability to sustain focus throughout the examination.

Whether testing can proceed for someone taking antipsychotic medication depends on a careful individual assessment. Factors include the specific medication and dose, the stability of the treatment regimen, the individual’s current mental state, their cognitive functioning, and the clinical context. In some cases, testing will be entirely appropriate. In others, the examiner may determine that the medication’s effects on physiological reactivity or cognitive capacity make valid testing impracticable on that occasion. This is a professional judgement that must be made on a case-by-case basis.

Mental Health Conditions and Polygraph Testing

Medication does not exist in isolation — it is prescribed for conditions that themselves warrant consideration. The following sections address common mental health presentations and how they relate to the polygraph process.

Generalised Anxiety Disorder (GAD)

GAD is characterised by persistent, excessive worry across multiple domains, often accompanied by physical symptoms including muscle tension, fatigue, difficulty concentrating, irritability and sleep disturbance. Individuals with GAD typically present with elevated baseline autonomic arousal.

As discussed above, elevated baseline arousal does not prevent valid polygraph testing. The examination is designed to detect differential responses, not absolute arousal levels. However, individuals with GAD may benefit from a longer pre-test interview to establish rapport and reduce situational anxiety, clear and unambiguous question wording to reduce worry-driven rumination, and explicit reassurance about the nature of the testing process. A patient, well-structured pre-test phase can make a significant difference to the comfort and validity of the examination for someone with GAD.

Panic Disorder

Panic disorder involves recurrent, unexpected panic attacks — sudden surges of intense fear or discomfort accompanied by symptoms such as rapid heartbeat, sweating, trembling, shortness of breath, chest pain and feelings of unreality or loss of control. The possibility of experiencing a panic attack during a polygraph examination is an understandable concern.

If a panic attack occurs during testing, a responsible examiner will pause the examination, ensure the individual is safe and comfortable, and allow them time to recover. Testing can then resume if the individual feels able to continue, or it can be rescheduled for another date. A panic attack during an examination is not interpreted as evidence of deception — it is recognised as a clinical event that is managed appropriately.

For individuals with a known history of panic disorder, it is helpful to discuss this during the pre-examination screening process, so that the examiner can plan accordingly. This might include scheduling additional time, choosing a particularly quiet and controlled environment, and agreeing on a protocol for managing any acute episodes.

Post-Traumatic Stress Disorder (PTSD)

PTSD presents particular considerations for polygraph testing. The condition involves re-experiencing traumatic events through intrusive memories, flashbacks or nightmares; avoidance of trauma-related stimuli; negative changes in cognition and mood; and heightened arousal and reactivity (hypervigilance, exaggerated startle response, difficulty concentrating, irritability).

The hyperarousal symptoms of PTSD can elevate baseline physiological activity, and the exaggerated startle response may produce pronounced reactions to unexpected stimuli, including the auditory presentation of questions. More significantly, if the subject matter of the examination is closely related to the individual’s traumatic experience, there is a risk that relevant questions could trigger trauma-related physiological responses that are distinct from deception-related responses but may be difficult to differentiate physiologically.

This does not mean that individuals with PTSD cannot undergo polygraph testing. It means that the examiner must exercise particular care in question formulation, ensuring that questions are crafted to address the specific issue under investigation without unnecessarily activating trauma-related material. The pre-test interview should include a thorough discussion of the individual’s PTSD history, current symptom severity, triggers, and any ongoing therapeutic treatment. Where the examination topic overlaps significantly with the individual’s trauma history, the examiner must consider whether valid differentiation between trauma responses and deception responses is achievable.

Depression

Major depressive disorder can be associated with psychomotor retardation (slowed physical and cognitive processing), fatigue, difficulty concentrating, and reduced emotional responsiveness. Some individuals with severe depression present with notably reduced physiological reactivity — a flattened autonomic profile that makes differential responding less pronounced.

For individuals with mild to moderate depression who are stable on medication and functioning in their daily lives, polygraph testing is generally appropriate. For individuals experiencing a severe depressive episode with marked psychomotor retardation, cognitive impairment or significant medication effects, the examiner may need to consider whether valid testing is achievable at that time. Depression can also affect an individual’s ability to engage meaningfully with the pre-test interview, understand and retain question content, and maintain sustained attention during the test phase.

How a Professional Examiner Adapts the Process

A common misconception is that polygraph testing is a rigid, one-size-fits-all procedure. In reality, a significant portion of an experienced examiner’s skill lies in their ability to adapt the process to the individual before them — without compromising the scientific validity of the examination.

The Pre-Test Interview: Where It All Begins

The pre-test interview is the most important safeguard against medication or mental health conditions compromising the examination. During this phase, the examiner will:

Gather a full medical and medication history — including current medications, doses, timing of last dose, recent changes, and any history of substance use.
Assess current mental state — observing the individual’s presentation, asking about sleep, mood, anxiety levels, and any acute symptoms.
Evaluate capacity and suitability — determining whether the individual is able to understand the process, provide informed consent, and engage meaningfully with the examination.
Explain the process thoroughly — demystifying the equipment, the question format, and what the examinee can expect, which itself reduces anxiety significantly.
Review and refine test questions collaboratively — ensuring that every question is clearly understood, unambiguous, and answerable with a definitive “yes” or “no.”
Establish informed consent — confirming that the individual understands their rights, including the right to withdraw at any point.

This interview typically lasts between 45 minutes and two hours, depending on the complexity of the case and the needs of the individual. It is not a hurried process. A thorough pre-test interview provides the examiner with all the information they need to make an informed decision about whether to proceed, to adapt, or to decline to test on that occasion.

Environmental and Procedural Adaptations

Beyond the pre-test interview, an experienced examiner may make a range of practical adaptations for anxious examinees or those with mental health conditions:

Extended familiarisation period — allowing additional time for the individual to become accustomed to the equipment and the testing environment before recording begins.
Controlled environment — ensuring the testing room is quiet, comfortably lit, and free from distractions.
Scheduled breaks — offering rest periods between chart collections for individuals who may struggle with sustained concentration or who are managing anxiety.
Adjusted pacing — delivering questions at a pace that accommodates the individual’s processing speed, particularly relevant for those taking sedating medications or experiencing cognitive effects of depression.
Additional chart collections — collecting more data sets than usual to compensate for any increased variability in physiological responding.
Post-test debriefing — providing a clear, empathetic explanation of what happened during the examination and what the results mean.

The mark of a competent examiner is not that they treat every individual identically, but that they maintain scientific rigour whilst responding with flexibility and professional sensitivity to the unique presentation of each examinee.

When Testing Should Not Proceed

Professional responsibility sometimes requires an examiner to decline to conduct a polygraph examination. This is not a failure — it is a safeguard. There are circumstances in which proceeding with testing would be clinically inappropriate, ethically indefensible, or scientifically unsound. These include:

Acute psychiatric crisis — individuals experiencing active psychotic symptoms, acute mania, severe dissociative episodes, or suicidal ideation should not undergo polygraph testing. Their physiological responses may be driven by the psychiatric condition rather than the examination questions, and the process itself could exacerbate their distress.
Severe dissociation — dissociative states can fundamentally alter an individual’s physiological responding and their subjective experience of the examination. If an individual is significantly dissociated, they may not be psychologically “present” during testing in a way that permits valid assessment.
Significant cognitive impairment — where an individual lacks the cognitive capacity to understand the questions being asked, to distinguish between question types, or to provide meaningful “yes” or “no” responses, the examination cannot produce valid results.
Recent medication changes — as discussed above, a recent initiation, discontinuation or significant dose change of psychiatric medication may place the individual in a physiologically transitional state that is unsuitable for testing.
Acute intoxication or withdrawal — individuals who are under the influence of alcohol or non-prescribed substances, or who are experiencing withdrawal symptoms, should not be tested.
Inability to provide informed consent — if the individual does not understand what they are consenting to, the examination must not proceed, regardless of the reason for the impaired capacity.

For a comprehensive discussion of situations in which polygraph testing is clinically contraindicated, see our article on when a polygraph examination should be refused.

When an examiner determines that testing should not proceed, this decision is communicated clearly and respectfully. It is not a judgement about the individual’s character or truthfulness — it is a professional determination that the conditions necessary for a valid and ethical examination are not present on that occasion. Testing can often be rescheduled for a later date when the individual’s circumstances have changed.

What You Should Do Before Your Examination

If you are concerned about how your anxiety or medication might affect your polygraph examination, the most constructive step you can take is to communicate openly with your examiner. The following practical guidance may help:

Disclose all medications — provide a complete list of everything you take, including over-the-counter medications and supplements. There is no judgement involved; this information helps the examiner conduct the most accurate assessment possible.
Take your medication as normal — do not skip doses, reduce doses, or take additional medication in anticipation of the examination. Your examiner needs you in your normal physiological state.
Mention any recent changes — if your medication has been changed in the past few weeks, let the examiner know. They can then assess whether postponing the examination would be advisable.
Share your diagnoses — if you have been diagnosed with any mental health condition, sharing this information helps the examiner adapt the process appropriately.
Discuss your concerns — if you are worried about panic attacks, anxiety, or any other aspect of the process, raise this during the pre-test interview or, better still, before the examination day itself.
Read about the process — familiarising yourself with what to expect during a polygraph examination can significantly reduce anticipatory anxiety.
Get adequate rest — attend your examination well-rested and having eaten normally. Fatigue and hunger can amplify anxiety and reduce cognitive sharpness.

The Centre for Forensic Neuroscience provides a confidential pre-examination screening questionnaire that allows you to share medical and psychological information before your appointment. This ensures your examiner is fully informed and can plan any necessary adaptations in advance, rather than discovering relevant information for the first time on the day of testing.

Countermeasures, Self-Medication and What Not to Do

It is important to address a related concern directly: the temptation to “self-medicate” before an examination.

Some individuals, understandably anxious about the process, consider taking a benzodiazepine, a herbal sedative, a large dose of an antihistamine, or even alcohol before attending their examination. This is strongly inadvisable for several reasons:

It may constitute a countermeasure — deliberately altering your physiological state to influence the outcome of a polygraph examination is classified as a countermeasure attempt. Trained examiners are alert to the signs of pharmacological suppression, and a suspected countermeasure attempt will be noted in the examination report.
It can invalidate results — if your physiological reactivity is suppressed to the point where differential responding cannot be detected, the examination cannot produce a valid outcome. This means the examination may need to be repeated — at additional cost and inconvenience.
It may cause harm — taking unprescribed medication carries clinical risks, particularly if combined with existing prescribed medication.
It undermines your position — if you are undergoing a polygraph examination to demonstrate your truthfulness, arriving in an artificially altered state does not serve that objective.

The most effective preparation for a polygraph examination is not pharmaceutical — it is informational. Understanding how the process works, what to expect, and why your anxiety will not cause you to “fail” is far more effective at reducing apprehension than any medication.

A Note on Transparency and Professional Honesty

We believe it is important to be transparent about what we do and do not know. The polygraph is a well-researched but imperfect instrument. Meta-analytic evidence suggests that properly conducted examinations achieve accuracy rates that are substantially better than chance and better than most other forms of credibility assessment — but they are not infallible. No diagnostic tool in medicine, psychology or forensic science achieves perfect accuracy.

What we can say with confidence is that anxiety and common psychiatric medications, when properly accounted for, do not represent a systematic threat to the validity of polygraph results. The published literature does not support the claim that anxious individuals routinely produce false positive (deceptive) results, nor that standard psychiatric medications reliably defeat the polygraph. The greater risk to validity comes not from the examinee’s mental state, but from poor professional practice — examiners who fail to conduct thorough pre-test interviews, who do not gather medication histories, who use poorly constructed questions, or who apply rigid procedures without regard to individual needs.

This is why the choice of examiner matters at least as much as any concern about your own anxiety or medication. An appropriately qualified, experienced examiner with clinical awareness and professional integrity will produce results that are as reliable as the methodology allows. An examiner who lacks these qualities will not — regardless of whether the examinee is anxious, medicated, or neither.

Summary: What to Take Away

If you are worried about how anxiety or medication might affect your polygraph examination, the following points may provide some reassurance:

Anxiety alone does not cause false results — the polygraph measures differential physiological patterns, not absolute arousal levels. Nervousness affects all responses relatively equally and does not systematically bias the outcome.
Most common medications are compatible with testing — SSRIs, SNRIs, ADHD medications, and many other commonly prescribed medications do not prevent valid polygraph examinations when taken at stable doses.
Some medications require particular attention — benzodiazepines, beta-blockers and antipsychotics can affect specific physiological channels, but a competent examiner can account for these effects when they are disclosed.
The pre-test interview is your safeguard — this is where your examiner gathers the information needed to adapt the process and ensure a fair, valid examination.
Disclosure is essential — honest, complete disclosure of your medications, diagnoses and concerns is the single most important thing you can do to ensure accurate results.
Testing should not proceed in certain circumstances — acute psychiatric crisis, severe dissociation, significant cognitive impairment, recent medication changes, and inability to consent are all grounds for postponing an examination.
Do not self-medicate — taking unprescribed medication to “calm down” before an examination is counterproductive and potentially harmful.
Choose your examiner carefully — the examiner’s clinical awareness, experience and professional standards are your most important protection against inaccurate results.

Your anxiety about the process is normal, understandable, and something that every competent examiner has encountered many times before. It is not something to be ashamed of, and it is not something that will undermine your examination. What matters is that you attend your examination honestly, that you disclose relevant information, and that your examiner has the professional skill and clinical awareness to conduct the examination with the care it deserves.

If you have specific concerns about how your medical history, medication or mental health may affect a polygraph examination, the Centre for Forensic Neuroscience welcomes confidential enquiries. We would always rather discuss your situation in advance than have you arrive on the day carrying unnecessary worry. You can contact us directly or complete our pre-examination screening questionnaire to share relevant information ahead of your appointment.