substance abuser       
noun [ C ] uk/ˈsʌb.stəns əˈbjuː.zər/ us/ˈsʌb.stəns əˈbjuː.zɚ/
 药物滥用者,吸毒者
someone who regularly uses illegal or harmful drugs
  About 70 percent of the street homeless are mentally ill or substance abusers or both. 大约70%的街头无家可归者是精神病患者或药物滥用者,或两者都是。 
 See: substance abuse
 - More examples
 - Often, substance abusers leave jail, relapse into drug use and criminal activity, and return to jail.
 - Most substance abusers are in denial.
 - a recovering substance abuser
 - Many of the mentally ill are also substance abusers.