A 37-year-old woman stopped taking paroxetine abruptly after feeling better and now experiences dizziness and electric shocks. What is the most likely explanation for her symptoms?

• A. Serotonin syndrome
• B. Paroxetine withdrawal reaction
• C. Depression relapse
• D. Anxiety relapse

Answer: (B)

Abruptly stopping an SSRI can trigger a discontinuation (withdrawal) syndrome. Paroxetine has one of the shortest half-lives among antidepressants, so its levels drop quickly after stopping. That rapid decline in serotonergic activity can produce dizziness and electric shock-like sensations (often described as “brain zaps”), along with other symptoms such as headaches, sleep disturbances, flu-like feelings, and irritability. These signs typically begin within a day or two and improve within days to a couple of weeks if the medication is restarted or tapered off gradually.

Serotonin syndrome would involve excessive serotonergic activity and present with features like agitation, confusion, fever, sweating, tremor, and hyperreflexia or clonus—usually in the context of other serotonergic drugs or overdose, not just dizziness and electric shocks. A relapse of depression or anxiety would show a return of mood-related symptoms (depressed mood, anhedonia, worry) rather than the distinct sensory and autonomic-like symptoms seen with withdrawal.

So, the most likely explanation is a withdrawal (discontinuation) reaction from stopping paroxetine abruptly.