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Q. A coworker of mine lies so often and so freely that it’s hard to trust anything she says. She’s an older woman, so I’ve even wondered if she might be dealing with early-onset dementia. How can I address this situation?

Name withheld by request

A. Lies are deliberate misstatements. But you don’t sound convinced that your coworker is fibbing intentionally. If you think that she may have a health problem that’s causing her to say things that are wrong or untrue, then your ethical obligation is the same as if you saw her trip over a curb and hit her head on the sidewalk: Offer her aid.

Here’s how you do that. The next time your coworker says something fallacious  that could cause problems for others at work, take her aside and ask if she’s aware that her statement was factually incorrect. Gauge her response. If she seems unsure or unsteady, your next conversation should be with your supervisor or someone in human resources who can put your colleague in touch with a health professional. And if it seems that she is purposely lying? Your forthright and direct approach should put her on notice to knock it off. If it doesn’t, you’ll need to loop in your boss and/or HR before anyone else’s work is compromised.

—Michelle Slatalla