In agreement with Trippin' and confusedinomicon -- don't be too hard on yourself, Secretum.
Had to laugh just now. Confusedinomicon, whenever I write your username, I have to look at it 2 or 3 times just trying to type it out.
On the subject in general, I never know what to think, because my mind is not consistent. I'm definitely very intelligent. It's equally true that there are a
lot of times I can't put a thought together to save my life. And times when it's so damn noisy up there, I can't hold a thought long enough to do anything with it before it vanishes. They're all true. Depression squashes my cognitive powers for sure. I don't remember that kind of unevenness and unpredictability years ago (in terms of day in/day out not knowing if Brain could be counted on to be in attendance). That unpredictability has made me less self-confident over the years, especially in terms of work.
Everything has to be written down, or done
right then or I will forget it. It's annoying, but... meh, whatever, carry a pen, right? Memory is amazing for some things (short or long term), yet I usually couldn't tell you what (or even if) I've eaten that day. Or what day it is. But quote reams of dialogue, even for things I haven't seen in years? No problem. Other long term stuff is sketchy and altogether missing. On a "right now" conversation, I'll either be able to tell you exactly what's going on, or I'm tuned out and couldn't tell you a thing. Blah blah blah. Apparently there is an on/off switch. I just don't know where it is(!) Lol.
But to the specific questions... (rabbit trail much?

) Cognitive symptoms that interfere with everyday life? Yes. But see above. Attribute to BP? Hmmm. Yeah, a bunch of it probably is. Many many years of untreated episodes have wreaked their havoc. I'm undecided if meds have had any real negative cognitive effects for me, because there are sooo many other factors to consider too...substances, age, sometimes overwhelming levels of stress, and a mind that's naturally all over the place. (Welcome to Rabbit Trail City!

A place for which there are no maps! Good luck!). They all undoubtedly play their parts as well.