"Nervous System" originally appeared on the band's debut EP, Turn to Red. It was then released in December 1979 on 7" vinyl by record label Island as the band's debut single. Both promo and non-promo versions of the single were released by Island Records with different cover art. The non-promo featured the same album cover as the Almost Red EP, while the promo featured an Island Records factory cover. The single did not chart.