Which of the following symptoms is indicative of serotonin syndrome?

Serotonin syndrome is a potentially life-threatening condition resulting from an excess of serotonin in the central nervous system. One of the hallmark symptoms of serotonin syndrome is confusion, which reflects the impact of elevated serotonin levels on the central nervous system. This can manifest as agitation, restlessness, altered mental status, or confusion, indicating that the brain's normal neurotransmission is disrupted.

While constricted pupils, severe sedation, and muscle weakness can be associated with other conditions or reactions, they are not characteristic of serotonin syndrome. In fact, serotonin syndrome typically involves symptoms like myoclonus, hyperreflexia, tremor, and pupillary dilation rather than constricted pupils. Additionally, sedation is usually not a prominent feature; instead, patients may exhibit increased activity or agitation. Therefore, confusion stands out as a key indicator of serotonin syndrome, aligning with the known clinical presentation of this serious condition.