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1977, from sick (adj.) in the mental sense + ending as in weirdo. Sickie "a pervert" is attested from 1972, and cf. sicknik (1959) "pervert, obscene comedian" (applied to Lenny Bruce), with fad ending -nik.
The craving and misery of an addict in need of a narcotic dose (1940s+ Narcotics)
[modern use of first sense from about 1955 is probably not a survival]