Six years ago after a suicide attempt I spent ~3 months in a residential care facility (aka "rehab") for women. The women there had all sorts of mental illnesses, ranging from depression to addiction to self-harm to eating disorders.

New girl arrives at the facility and she seems cool. We have a few conversations about how shitty the facility is, how the staff are borderline abusive at times, etc. She says she's there for depression and we bond over it a little bit. She's type I diabetic.

One day she confesses to me that the nurses have been coming in her room at night and messing with her insulin pump while she's sleeping to try to kill her. At the time I just nodded along like yeah, that's fucked up, but alarm bells started going off in my head. Over the course of the next several days it comes out that she's not just there for depression/bipolar, but pseudologia fantastica. She's a compulsive liar.

After treatment she stole credit cards and a bunch of money from one of the more naive girls she met there. Not long after that she killed herself. If you've never met a compulsive liar before, it's scary how normal they can seem at first. Sure, it was a rehab full of all kinds of crazy chicks who lied about shit like hiding tweezers and who threw up in so-and-so's jewelry box, but pathological lying takes it to a totally different level. I couldn't trust anything she said. When I heard about her death I almost felt a sense of relief at the fact that she's not causing her friends and family any more pointless suffering.