A client on an SSRI for six weeks reports confusion and is worried about their symptoms. Which question would be most important to ask to assess a serious adverse reaction?

• A. Are you having trouble sleeping at night?
• B. Do you have periods of muscle jerking?
• C. Are you having any sexual dysfunction?
• D. Is your mood improving?

Answer: (B)

The key concept is recognizing a potentially life‑threatening adverse reaction to an SSRI, namely serotonin syndrome, which can develop within weeks of starting or changing the medication. Serotonin syndrome shows neuromuscular and autonomic signs, with neuromuscular hyperactivity being especially important to detect early. Asking about periods of muscle jerking directly probes for a motor symptom that can signal this dangerous reaction. If a patient reports muscle jerking, along with confusion or agitation, it points toward serotonin syndrome and warrants urgent assessment and management.

Other common SSRI side effects like trouble sleeping or sexual dysfunction are important to monitor but do not indicate an immediate serious threat. A shift in mood isn’t itself a red flag for a dangerous reaction and could reflect treatment response or other issues.