addiction

• Cold turkey

  To abruptly stop an addictive habit or activity completely and without any gradual reduction.

• Fall Off the Wagon

  To relapse into an old bad habit, particularly alcoholism, after a period of successful abstinence.

• off the wagon

  To relapse into an addiction, especially alcoholism, after a period of sobriety.

• chasing the dragon

  To smoke heroin or opium, typically by heating it on foil and inhaling the rising smoke, or more broadly, the obsessive pursuit of an elusive and addictive high.

• mainlining

  Mainlining refers to injecting a drug, especially a potent one, directly into a major vein for an immediate and powerful effect.