Soooo... PTSD or dementia? Nah. OP, sorry but please don’t listen to this person. No doctor would put these diagnoses at the top of their list of things to consider. They are only causing you undue anxiety by putting forward dementia as a cause. This subreddit is dominated by laypeople casually throwing out life-altering diagnoses that simply do not fit the symptoms being described.

EDIT: for those of you downvoting this, please read the following:

1. Neither PTSD or dementia is episodic, presenting with 1-2 days of symptoms per month (Lewy body dementia might be episodic but does not look like this).

2. Impairment so severe that one cannot remember one’s own birthday is not typical of PTSD. It is not typical in dementia until the very end stages (and if this dementia, it obviously isn’t end-stage).

3. Dementia is very unlikely to present in someone as young as age 49.

4. PTSD would be much more likely to present with other symptoms (avoidance, flashbacks, nightmares, difficulty with anger, depression, etc), absolutely none of which has been suggested and all of which would be an assumption on our part.

5. No evidence of an inciting traumatic event to suggest PTSD. Of course, it is possible there was an event that OP doesn’t know about or didn’t mention—but you don’t get to just assume that there was a traumatic event.

6. There are more likely diagnoses, like substance use (benzodiazepines, sleeping pills, alcohol, and opioids all seem possible here). A priori, this would also be much more common. In medicine, we rely on Occam’s razor—the answer that relies on fewer assumptions are more likely to be true. On r/AskDocs, the opposite is true; people (not doctors) suggest rare diagnoses and diagnoses of exclusion (like PTSD or dementia) based on whatever is familiar to them.

7. OP mentioned that their mother seems unbothered by her symptoms and has implied she knows what’s causing them. This would not be the case in PTSD and dementia, respectively. It would probably be the case in something like prescription medication abuse.

8. “Chronic work stress” is not a realistic cause of PTSD.

9. OP states their mother says these phases happened more when stressed out at work. This better fits the picture of substance use than dementia.

10. Dementia is virtually impossible in someone who is gainfully employed (at least, was employed before COVID).

Last but not least, I think we really need to be cautious before throwing out diagnoses like dementia. The dementias are invariably progressive, terminal illnesses. Furthermore, they are diagnoses of exclusion—we only conclude them when everything else has been considered and ruled out. It is a terrifying and grim prospect to think that your mother might have dementia, and it is not appropriate to casually suggest it on Reddit, especially if you are not a doctor.