SSRI discontinuation syndrome, also known as SSRI withdrawal syndrome or SSRI cessation syndrome, is a withdrawal syndrome that can occur during or following the interruption, lowering of dose or discontinuation of regular SSRI or SNRI antidepressant drug usage. The condition often begins between 24 hours to one week after reduction in dosage or complete discontinuation, depending on the elimination half-life of the drug. The prescribing labels of SSRIs acknowledge the possibility of "intolerable" discontinuation reactions, and some patients have extreme difficulty discontinuing use from SSRI drugs.
Symptoms described as "brain zaps", "brain shocks," "brain shivers" or "head shocks" are a withdrawal symptom experienced during discontinuation (or reduction of dose) of antidepressant drugs.[6][7] The symptoms are widely variable in description and of unknown etiology;[7] common descriptions include dizziness, electric shock-like sensations, sweating, nausea, insomnia, tremor, confusion, and vertigo.[6][7] The MedDRA "preferred term" for coding these types of symptoms in adverse drug reaction reports (for use in pharmacovigilance databases such as under the Yellow Card Scheme), is paraesthesia.[8][9]
In a 1997 survey, a "sizable minority" of medical professionals were not confidently aware of the existence of antidepressant withdrawal symptoms.[10] A 2005 review of adverse event reporting showed that descriptions of "electric shocks" from patients on paroxetine had been reported more frequently than some other symptoms.[8]
