Can severe anemia/pernicious anemia cause similar symptoms to bran damage or dementia?

Yes: B12 deficiency can cause severe brain issues such as what you are describing.

In short, yes.: Pernicious anemia is another word for B12 deficiency anemia. B12 deficiency can cause impaired memory and inability to think and react quickly which is very similar to the way dementia affects the brain.

B12 deficiency: Yes, anemia can cause cognitive problems which may resemble delirium or dementia due to impaired absorption of vitamin b12. This vitamin is important for nerve function, and prolonged deficiency can cause permanent damage. If you are concerned about cognitive changes i suggest asking your doctor to run labs (i.e. B12 level, hcy, mma, and creatinine). I also recommend taking oral or im b12.