adhd
"Primary related symptom was mild cognitive impairment: memory in particular, almost entirely episodic memory (autobiographical memory: stuff that's happened to you, including events, names, etc.) & short-term memory. Thought I was developing Alzheimers. Severe enough to derail career, finally lost ability to work. 
Amantadine effects: built slowly, subtle but noticeable improvement in memory over 6 month period. Huge improvement after 2 yrs. Problems remain in calibrating decline & improvement; I've certainly improved some functionality enormously: can remember day-to-day events, plans, commitments; can remain aware of what I'm doing, keep up focus; can multi-talsk (limited but definite) so I can interrupt & resume interrupted activities..."