Almost all meds can have serious side effects and many of them can be toxic, if the pdoc doesn't use care with their individual patient, Lithium isn't anymore toxic than many of the others. Depakote can effect the liver, that is why my former pdoc use to send me for monthly bllod work, the Lithium was only every 3 to 6 months and for my bro it became once a year.
All medications have some sort of caveat.
Unfortunately for many of us it is time, patence, and a good pdoc to know what is the best ones for us to use, through physical and mental evaluation of his or hers patients.
Thanks so much for adding to this thread, all opinions, and input help others here, that is what support is all about

Stay well,
DE

In giving advice seek to help, not please your friend
SOLON