Is it true that psychiatrists are reluctant to prescribe just lithium to bipolar patients?

I just recently spoke to a woman who claims to have a doctorate in homeopathic medicine and who claims that nowadays, psychiatrists are often pressured by big pharma to not prescribe lithium, at least not by itself, because lithium is a naturally occurring salt and the pharmaceutical companies don't make a big profit from it. I know that lithium is a naturally occurring salt, but wouldn't the pharmaceutical companies still make a profit, since the lithium has to refined in some way and then packaged?