cur for all types of antidepressants.
Unlike withdrawal syndromes associated with  opioids, alcohol, and other substances
of abuse, antidepressant discontinuation sy ndrome has no pathognomonic symptoms. In-
stead, the symptoms tend to be vague and variable and typically begin 2–4 days after the
last dose of the antidepressant. For SSRIs (e.g., paroxetine), symptoms such as dizziness,
ringing in the ears, “electric shocks in the head ,” an inability to sleep, and acute anxiety are
described. The antidepressant use prior to discontinuation must not have incurred hypo-
mania or euphoria (i.e., there should be confidence that the discontinuation syndrome is
not the result of fluctuations in mood stabi lity associated with the previous treatment).
The antidepressant discontinuation syndrome is based solely on pharmacological factors
and is not related to the reinforcing effects of an antidepressant. Also, in the case of stim-
ulant augmentation of an antidepressant, abru pt cessation may result in stimulant with-
drawal symptoms (see “Stimulant Withdraw al” in the chapter “Substance-Related and
Addictive Disorders”) rather than the antide pressant discontinuation syndrome described
here.
Prevalence
The prevalence of antidepressant discontinu ation syndrome is unknown but is thought to
vary according to the dosage prior to discon tinuation, the half-life and receptor-binding
affinity of the medication, and possibly the indi vidual’s genetically influenced rate of me-
tabolism for this medication.
Course and Development
Because longitudinal studies are lacking, little is known about the clinical course of anti-
depressant discontinuation syndrome. Sympto ms appear to abate over time with very
gradual dosage reductions. After an episode, some individuals may pr efer to resume med-