Sister is having fals3 memories...

This type of confusion and distorted thinking/speech can be a symptom of psychosis as well. Some people with depression can develop psychosis.

Sounds like ADD and a side effect of her medication plus the depression - It can severely effect memory. I've sworn I've done something and become upset when challenged, but it turns out I did indeed forget to do something. I had thought about doing the task so much, that I thought I had done it. I have ADD and a few other mental health conditions.

Just be patient with her.

I am nearly 50 and have recently been diagnosed with Autism/Adhd. I'm a Huge 'masker', everyone always thought I loved social events, was always popular, but didn't have any really close friends. I have ocd tendencies, and when I'm tired and over think things, my brain convinces me that I've done them/said/seen things....eg sending thank you cards/Christmas cards etc, I've thought about it, even down to what I want to say, my brain then convinces me that I have actually done this, then between the autistic fear of "argh what will happen' when it is pointed out I haven't and the fear of being wrong, the fear that everyone will hate me/leave me etc for 'lying' more stories come spilling out. It's awful, it's like you have no control over what you are perceiving as real. Anyway, my family now understand where some of the stories I've told over the years have come from and are a lot more understanding, and it now just gets laughed about.

Is it possible your sister could be neurodiverse? Combine that with depression, lack of sleep and perimenopause and it's a toxic combination.... sending love ❤️

My MIL invented an entire scenario that included a marriage falling apart, desperate bids to fix it and a trip abroad...none of which happened. She was so invested though and spoke of it all like it was fact.

DH and I were pretty alarmed so now we're just keeping an eye on her mental health and behaviour and looking out for anything that seems abnormal.
There's not been anything since but if it happens again, we'll speak to her and then the next point of call is the dr.

It’s a known psychological condition that people confabulate when they dissociate, dissociation is associated with quite a good number of both personality disorders (borderline, narcissism etc) and mental disorders (bipolar, schizophrenia etc)

It is also well established that dissociation is almost universal, and that tiredness and stress can also be a cause so you may see it in people who are otherwise mentally healthy.

Memory is very fallible and it is not uncommon for people to remember things differently - last time this came up I quoted a researcher which upset some people so wont go there, but it is fairly well established in psychology that memory is not massively reliable. Why do people misremember? Could be tiredness, stress or being preoccupied. Or it could be that she has main character syndrome and has to relate everything to herself. Or she could be a fantasist - my mother was like this and my sister is very similar - will take things on and claim she did them, even when you do. If it is the last 2 though, it is probably obvious in other ways.

I sometimes also wonder was this real or was it in a dream and am a light sleeper, have insomnia and tired in the mornings. That sounds interesting, I hadn't known that about sleep apnea, so worth getting it checked out. As effects sleep quality and memory/memories.

It’s a known psychological condition that people confabulate when they dissociate, dissociation is associated with quite a good number of both personality disorders (borderline, narcissism etc) and mental disorders (bipolar, schizophrenia etc) Does she have any other symptoms? A mild OCD and depression could often be a symptom of PTSD that comes with dissociation. Has there been anything in here life could have caused her to have symptoms of PTSD?

I had a similar worry about a family member..have no update so not helpful.
She is Late 40s and would talk about something happening a.couple of weeks ago and it would have happened 2 years ago...or talking about something from 2 years ago that actually happened a week or so ago
And yet she'd argue she was right when everyone else knew she wasn't.
If.it was happening to me I'd be a bit worried I think

Strangely I was there and that is what she meant- she wanted to open it.

Yes, I can see how it’s easy to do when it’s a memory from a long time ago. I think some of it is self preservation too. Rose tinted glasses maybe.

Mil often changes/adds details to stories or things that have happened recently too. She is adamant it happened that way.

Dhs mum is similar to this.

She often rewrite stories to fit her preferred version of events. The scary thing is, she really seems to believe what she is saying.

She rewrites dh & his 2 siblings childhood, usually to make herself come across better.
Seemingly mundane things like ‘I always cooked for you kids’
Dh and his siblings have all privately said this is far from the truth, they’d regularly go to their nans most nights as it was the only way they’d get their tea or she’d send them to the corner shop to get their own because she ‘didn’t want to mess up her kitchen’ according to dhs older brother.

She’s been like this for years & years, so it’s not a recent thing or solely age related.

When we're seated and not even left the terminal yet, my sister says - oh you can't open the window. I gave her a withering look and said do you want to die? Then explained why you can't open plane windows. We were still on the ground and Mum didn't hear any of this.

I told her about it after the holiday. That sister asked if the windows open. Mum thought it was hilarious.

When I read that though, it doesn't read to me as if your sister actually asked if the windows opened.

I mean tbh that's the sort of stupid thing I might say without thinking!

I’ve known two people who did this often enough for it to be noticeable. First was one of my parents. The misremembering or exaggeration of actual events seemed to be about control or simply embarrassing whoever they were speaking about. They did go on to develop early onset Alzheimer’s.

Second was my ex. Has autistic traits and would argue the sky is green and grass is purple if that’s what he’s convinced himself is true. I have told him things and he’d reiterate them to me but with certain details changed - ‘yeah that time your friend deliberately pushed you into the road’ ‘no, that didn’t happen, my friend fell whilst we were out walking??’. Then every time that friend was mentioned he said ‘oh the one that pushed you into the road?’. It was bizarre and made me question my own memory of things (considering the first example I gave was the last thing I needed).

DS adds details that never happened, as often to his detriment as his advantage. He has autism and fairly severe OCD, and I think the churning trapped thoughts produce their own 'reality'. For instance, when he came off the road in his crappy old car, he told us he was speeding and should have known better, really berated himself for it -- but his black box said he was doing 25 mph.

I suspect I do it too when stressed or sleep deprived. I'd be a shit witness in court.

This is the sort of thing I meant @ALittleAlarmed - maybe the language in my post was too strong, but I meant this sort of adopting stuff as truth. It's very common.

My mum always did this. It was so annoying. You tell her something that happened and she'd misremeber it and add to it that she was there and how funny it was. It was annoying rather than anything else.

One such example being - we got on a plane as teens. We weren't frequent flyers and hadn't flown since early childhood.

When we're seated and not even left the terminal yet, my sister says - oh you can't open the window. I gave her a withering look and said do you want to die? Then explained why you can't open plane windows. We were still on the ground and Mum didn't hear any of this.

I told her about it after the holiday. That sister asked if the windows open. Mum thought it was hilarious.

Later on Mum told the story as follows :

Remember when we were flying and over the mountains mid flight your sister said - it's stuffy in here can you open the window and we had to tell her why?! Then collapses laughing - so funny she wanted the windows open mid flight over the mountains.

No matter how many times I told her that is not what happened and that she didn't even hear it and we were in the ground...she insisted I was wrong. She was only 50s at the time.

She did it with many things. So many other stories she took as her own, embellished and swore she remembered what never happened.

I don't know what it is.

I would say something to her partner and then also to her, especially if he agrees. Probably nothing, but there are some brain illnesses/problems that can do this so, depending on the partner's/her response, it would be worth a trip to the doctor.

I'm going to come out with my favourite line - I think I've used this about 20 times now - but my son who is Neurodivergent Autistic/ADHD does this.

He is not an intentional liar. He's incredibly truthful and seeks truth. But there is often distortion on how something played out, for example oh when you told me x,y,z mum. I'm like no I didn't say that, what happened was x,y,z. I see he really does remember it being said and isn't lying.

My son might also say he just replied to my question when he didn't even speak. In his mind he answered me and thought he had verbalised it when he hadn't.

Ooh yes, that's my sister also-retelling something but from her pov & as if she was there!

MIL and DH do that as well - but if it's recent on questioning it does come out they weren't there - over time and retelling that goes and they really seem to think they were there.

Though even when they are there the stories can be so far from reality you don't recognise event. I was with MIL in crowded London pub when handbags kept getting pulled back in crowd- she laughed at me clutching mine to front- next place we find her bag had money taken. Few year later up at IL she telling story and it's so dramatic - turned to FIL with some comment - and he say you were there - it took ages to work out it was that event so little was what I remembered.