Addict

a person who is to an activity, habit, or substance:
a drug addict.
to cause to become physiologically or psychologically dependent on an substance, as alcohol or a narcotic.
to habituate or abandon (oneself) to something compulsively or obsessively:
a writer addicted to the use of high-flown language; children addicted to video games.
contemporary examples

but the majority of the time is spent dissembling the system that has enabled the addict to finance and feed their affliction.
the rehab show that works natasha vargas-cooper july 20, 2010

“what would make him an addict is if his behavior gets in the way of his day-to-day functioning,” says one psychologist.
can s-x-addiction rehab save tiger? abby ellin december 17, 2009

the most moving material in bomb feels like a rehash: care-taking the father, painfully recalling his suicidal, addict mother.
why some memoirs are better as fiction taylor antrim january 18, 2010

then there is the nicotine: a stimulant that for the addict also has the added effect of calming the nerves.
my (electronic) cigarette addiction eli lake january 30, 2013

i was an addict back then—meth, heroin, cocaine—you name it, i was hooked.
the real ‘breaking bad’: confessions of a former meth king mark sullivan july 16, 2011

historical examples

and it is a very risky thing for a woman to marry an addict with the idea of reforming him.
woman william j. robinson

he decided that she must be an addict of some drug, perhaps like the black lotus of xuthal.
the devil in iron robert e. howard

if we addict ourselves to the vices of the age, can we warn the people against them with any hope of success?
the sheepfold and the common, vol. i (of 2) timothy east

he’s a man dressed in a weird outfit out of an addict’s nightmare and appears to be the boss of this crew of rugged campers.
the ethical engineer henry maxwell dempsey

he was a gambler and this talk was like the taste of drugs to an addict.
deathworld harry harrison

verb (əˈdɪkt)
(transitive; usually p-ssive) often foll by to. to cause (someone or oneself) to become dependent (on something, esp a narcotic drug)
noun (ˈædɪkt)
a person who is addicted, esp to narcotic drugs
(informal) a person who is devoted to something: a jazz addict
v.

1530s (implied in addicted), from latin addictus, past participle of addicere “to deliver, award, yield; give -ssent, make over, sell,” figuratively “to devote, consecrate; sacrifice, sell out, betray” from ad- “to” (see ad-) + dicere “say, declare” (see diction), but also “adjudge, allot.” earlier in english as an adjective, “delivered, devoted” (1520s). related: addicted; addicting.
n.

1909, in reference to morphine, from addict (v.).

addict ad·dict (ə-dĭkt’)
v. ad·dict·ed, ad·dict·ing, ad·dicts
to become or cause to become compulsively and physiologically dependent on a habit-forming substance. n. (ād’ĭkt)
one who is addicted, as to narcotics.
ad·dic’tive adj.