A client receiving a selective serotonin reuptake inhibitor arrives at the mental health clinic complaining of dizziness, nausea, and agitation. She reports she was out of town for several days and forgot her medications. What is the likely cause of her symptoms?

Choice A reason: Serotonin discontinuation syndrome occurs when SSRIs are abruptly stopped. Symptoms include dizziness, nausea, agitation, flu-like symptoms, and sensory disturbances. It typically arises within days of missed doses and resolves with resumption or gradual tapering of the medication. Choice B reason: Cholinergic crisis is associated with excessive acetylcholine activity, often due to overmedication with cholinesterase inhibitors. It presents with muscle weakness, bradycardia, and respiratory distress—not typical of SSRI withdrawal. Choice C reason: Serotonin syndrome results from excessive serotonergic activity, often due to drug interactions or overdose. It presents with hyperreflexia, clonus, fever, and altered mental status. It is not caused by missed doses. Choice D reason: Neuroleptic malignant syndrome is a rare, life-threatening reaction to antipsychotics, characterized by rigidity, hyperthermia, autonomic instability, and altered consciousness. It is unrelated to SSRI discontinuation.