Are lie-detectors used in psychiatry? Why or why not?

It seems that polygraphs (“lie-detectors”) could be a useful aid to psychiatrists/psychologists in therapy. For example: Doc asks, “How do you feel about that?” Patient answers: “I feel fine about it.” Doc looks at polygraph, then replies, “I don’t think you’re being honest with me or with yourself…”

Are they now or have they ever been used in such a manner? Why or why not? Too difficult to operate? Too slow to return a response (i.e., the results require analysis minutes or hours after the utterance, rather than activating an instantaeous cartoonish blinking red light and buzzer everytime someone lies)? Too unreliable to trust? Too intimidating for already-distressed patients? Not, in the end, significantly more effective in ferreting out truth/lies than a reasonably well trained therapist?

Are lie-detectors used in psychiatry? Why or why not?

I have never heard of them being used on any wide scale (or at all really). Patients have to volunteer for and consent to most types of treatment. That wouldn’t work well with polygraphs. Patients are often under a lot of emotional strain and being hooked up to a supposed mind reading device would not help that at all. The inevitable false positives would not be good for doctor-patient relations. Finally, the psychiatrist is supposed to doing some actual treatment with the patient, not giving a polygraph quiz. It is hard to see how this would benefit anyone and all and it would hurt in a lot of ways.

The only time I have ever seen anything like this in use was group therapy for substance abuse. Group members volunteer to share with others and listen to get help. If the group leader suspects a participant isn’t telling the truth, he/she will give a drug screening during break or after the session and the person can be kicked out of the group if it comes back positive.

First of all psychiatrists and psychologists and other mental health workers should be trained to detect fudging by their patients. But even better than this, the therapist is there to HELP the person.

If a person is lying to the person they are supposed to be seeking aid from this often will tell the therapist MORE than if the truth is told.

No reputable therapist will treat a client who doesn’t want to help themselves. So if a therapist can detect errors in the story they can see WHY the stories conflict and explore that area of the patient’s problem.

Nope. I don’t conduct my therapy sessions with the assumption that the client is lying, or that my job it to play “gotcha!” If a client wants to lie on purpose, that’s really their lookout about how to spend their money (in a non-forensic situation). If they’re misrepresenting because they don’t quite know that they’re experiencing a discrepancy, I assure you that pointing this out in a definitive or triumphant way will not cause the person to have insight or thank you.

We’re generally fairly terrible at it, and as most people do, tend to overestimate how good we are at it. Very very few people are really good lie detectors.

We often dont really need to be good at it though, other than in some very limited contexts, eg sexual offenders, where really its a police matter anyhow and best handled as a separate thing in my view. Im assuming this is more how it could be useful as a therapeutic tool than a forensic one like sexual offenders, where the answer is pretty obvious, if its an effective tool.

Therapeutically, one obvious problem is that cynicism is often a great way to lose rapport with a patient/client, and the quality of relationship with the client is one of the better predictors of therapy success. I cant really see how a lie detector would be particularly useful in general practise, in that you’re basically making someone tell the truth before they’re ready, and adding a lot of stress to a session to boot.

I cant give any specific cites though, Id be surprised if someone hadnt tried it somewhere, but would be surprised if it was in non forensic settings.


The polygraph is simply not reliable.
That’s why it’s not admissable in court (for example).