Reverse tolerance or sensitization is the phenomenon of a reversal of the side-effects from a drug, or the reduction of insensitivity caused after drug tolerance has been established, or in some cases an additional increase of effects with continued use of a single drug existing alongside or not to a tolerance for other aspects of the same substance.. Typically this involves the use of an additional medication, or abstinence from a drug for a period of time, known as a drug holiday

Drug holiday

A drug holiday is when a patient stops taking a medication for a period of time; anywhere from a few days to many months or even years if they feel it is in their best interests.Planned drug holidays are used in numerous fields of...

. Such drugs include amphetamines, or SSRIs.
As a result, regular users commonly experience a quick decrease of unwanted side effects, without an equivalent loss of its stimulant properties. Notably, the sensitization is induced more quickly, and persists far longer than withdrawal-related effects, suggesting a phenomenon more complex than a simple tolerance-induced withdrawal

Withdrawal

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, recreational drugs, and alcohol...

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