Reverse tolerance

Addiction and dependence glossary
• addiction – a state characterized by compulsive engagement in rewarding stimuli despite adverse consequences
• addictive behavior – a behavior that is both rewarding and reinforcing
• addictive drug – a drug that is both rewarding and reinforcing
• dependence – an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake)
• drug sensitization or reverse tolerance – the escalating effect of a drug resulting from repeated administration at a given dose
• drug withdrawal – symptoms that occur upon cessation of repeated drug use
• physical dependence – dependence that involves persistent physical–somatic withdrawal symptoms (e.g., fatigue and delirium tremens)
• psychological dependence – dependence that involves emotional–motivational withdrawal symptoms (e.g., dysphoria and anhedonia)
• reinforcing stimuli – stimuli that increase the probability of repeating behaviors paired with them
• rewarding stimuli – stimuli that the brain interprets as intrinsically positive or as something to be approached
• sensitization – an amplified response to a stimulus resulting from repeated exposure to it
• tolerance – the diminishing effect of a drug resulting from repeated administration at a given dose

Reverse tolerance or drug sensitization is the phenomenon of a reversal of the side-effects from a drug, the reduction of insensitivity caused after drug tolerance has been established, or, in some cases, an increase in specific effects of a single drug existing alongside a tolerance to other effects of the same substance. Typically this involves the use of additional medication or abstinence from a drug for a period of time, known as a drug holiday. Such drugs include amphetamines and SSRIs.

As a result, regular users commonly experience a quick decrease of unwanted side effects, without an equivalent loss of its stimulant properties.

See also

• Desensitization (medicine)
• Downregulation and upregulation