Do psychologists know when people are lying?

[DilemmaEmma2]

Might be a stupid question.
Family court have instigated another psychological assessments as ex got report thrown out..
I feel he now knows how to behave and what to say.. he's a very good liar.

This is something I am interested in also as I am wondering whether mine will end up down this route.

As far as I am aware from reading around some can from the way they carry it out and some have been caught that way but I'm not sure how common that is. I've read some where multiple experts have formed an opinion but again not sure how often that occurs.

Quite

Nope. I lied to one and he had no idea - signed me off as recovered (I wasn't). I was on suicide watch and my appointment was the day after I'd swallowed a load of pills. I was so depressed I could barely function. I wasn't hiding it. He asked if I felt better, I said yes and he believed me. Perhaps he was a particularly poor psychiatrist but he accepted my assertion. They are certainly not infallible.

No, why would you lie though? They’re trying to help you. It’s like going into a doctor and saying you don’t have a broken leg when you do - pointless and a waste of everyone’s time. They might be able to identify inconsistencies in your narrative over a session or two though.