Corey Moss, writing for MTV News opined that the song was possibly "even more depressing" than Nirvana's eponymous song from 1992. "Rolling Stone"s Rob Sheffield described "Lithium" as Lee's ode to Kurt Cobain. In his review of "The Open Door", Andy Gill from "The Independent" listed "Lithium" as one of the album's standout tracks; he further noted that it perfectly captures the album's mood "wreathed in the genre staples of black-clad, mascara'd gloom" through lyrics such as "I want to stay in love with my sorrow/ Oh, but God I want to let it go". Stephen Thomas Erlewine highlighted the "churning" song as one of the three best on the album. He felt that it was reminiscent of the tracks prevalent on the band's debut album, characterized by similarity to Tori Amos's material and observed that on "The Open Door", this type of songs were "ushed to the background". In an album review, Sara Berry from "St. Louis Post-Dispatch" opined that "The band deftly balances scorching rock anthems with reflective, piano-heavy ballads like 'Lithium'". IGN's Ed Thompson wrote that Lee's "gentle tickling of the ivories" is notably present on "Lithium".