Which is a symptom of serotonin syndrome?

Serotonin syndrome is a potentially life-threatening condition that occurs due to an excess of serotonin in the brain, often as a result of certain medications or drug interactions. One prominent symptom of serotonin syndrome is restlessness, which manifests as an inability to remain still or calm. Often, this restlessness can be accompanied by hallucinations, where an individual may experience sensory perceptions that do not correspond to reality. These symptoms arise from the overstimulation of serotonin receptors in the nervous system, leading to heightened activity and agitation.

The other options do not align as closely with the hallmark symptoms of serotonin syndrome. Severe fatigue and drowsiness are more commonly associated with other conditions or the sedative effects of medications. Slow heart rate and confusion can occur in various medical conditions but are not specific indicators of serotonin syndrome. Joint pain and inflammation also do not relate to serotonin excess and are typically associated with inflammatory or autoimmune conditions rather than neurochemical imbalances. Thus, restlessness and hallucinations are accurate reflections of serotonin syndrome's impact on mental and neurological function.