It's hard to figure out because depression can for sure cause it. And as we age our memory gets worse. I type very fast and when I go back and read it I notice I typed had instead of has or on instead of in or if instead of of. Simple mistakes but always the same type of word. Prepositions I think they are. Whatever they are it is always the same type which makes me suspect. I too draw blanks sometimes. I am 50 and attribute some of it to age but I think my meds are causing something too. Years ago at high doses of Efffexor it affected my short term working memory. Especially driving. I had to lower the dose and I was fine.