Helping Americans Seek Treatment Act of 2018 This bill amends the Public Health Service Act to require the Substance Abuse and Mental Health Services Administration (SAMHSA) to conduct a national public awareness campaign regarding its substance abuse treatment referral routing programs. SAMHSA must incorporate into its programs and services information about pre-arrest referral programs, which allow an individual with a substance use disorder to seek assistance from a law enforcement agency without being subject to criminal penalties related to the individual's possession and use of controlled substances.