Withdrawal can refer to any sort of separation, but is most commonly used to describe the group of symptoms that occurs upon the abrupt discontinuation/separation or a decrease in dosage of the intake of medications and recreational drugs (including alcohol). In order to experience the symptoms of withdrawal, one must have first developed a physical/mental dependence (often referred to as chemical dependency). This happens after consuming one or more of these substances for a certain period of time, which is both dose dependent and varies based upon the drug consumed. For example, prolonged use of an anti-depressant is most likely to cause a much different reaction when discontinued than the repeated use of an opioid, such as heroin. In fact, the route of administration, whether intravenous, intramuscular, oral or otherwise, can also play a role in determining the severity of withdrawal symptoms. There are different stages of withdrawal as well. Generally, a person will start to feel worse and worse, hit a plateau, and then the symptoms begin to dissipate. However, withdrawal from certain drugs (benzodiazepines, alcohol) can be fatal and therefore the abrupt discontinuation of any type of drug is not recommended.^{[citation needed]} The term "cold turkey" is used to describe the sudden cessation use of a substance and the ensuing physiologic manifestations.

Moon Knight is a fictional character, a superhero who appears in comic books published by Marvel Comics. The character exists in the Marvel Universe and was created by Doug Moench and Don Perlin. He first appeared in Werewolf by Night #32 (August 1975).

The character debuted in the title Werewolf by Night #32 (August 1975), written by Doug Moench with art by Don Perlin, as an enemy of the title character in a two part story continuing in issue #33. The character proved popular with readers, and was granted a solo spot in Marvel Spotlight #28-29 (1976), written by Doug Moench with art by Don Perlin.

He then had appearances in Spectacular Spider-Man issues #22 and #23, both written by Bill Mantlo with art by Mike Zeck on #22 and Jim Mooney on #23; Marvel Two-in-One #52, written by Steven Grant with art by Jim Craig; and Defenders #47-50. Moon Knight then gained a backup strip in the Hulk! Magazine in issues #11-15, #17-18, and #20, as well as Marvel Preview #21 (on which he was the cover feature), all written by Doug Moench. Art was done by Gene Colan in #11, Keith Pollard in #12, and Bill Sienkiewicz on the rest. These were reprinted in Moon Knight Special Edition #1-3.