every medication is a poison. some of the side effects are positive, such as penicillin killing bacteria, other side effects are not so good, like sodium cyanide being lethal.
i have been on lithium carbonate (900 mg) fo about 6 yrs. my hands have tremmors. oh, well. i'd rather have the tremmors than super depression followed my mania. unlike your friend, i do not get headaches.
there was a thread on here maybe a month ago (i have little concept of time, ask my wife
memory loss with certain meds. after reading the thread, i personally ame to the coclusion that the memory loss is a functio of the disease rather than od the meds. yes, i have memory loss all the time. sometimes it's severe, sometimes not. i don't know is there have been any scientific studies of this phenomenon (sp?).
your friend has an illness that is not currable, but is manageble. every so often his meds for controlling it may poop out and another "cocktail" will have to be tried. yes, tried. this illness reacts to meds very individually. what helps me may kill you. and, as i said, the meds need to be adjusted from time to time.
i hope this helps, iona.