What symptom is associated with serotonin syndrome?

Excess serotonergic activity is the hallmark of serotonin syndrome, which results from an overabundance of serotonin in the central nervous system. This condition often arises due to the use of multiple serotonergic medications or overdoses of such medications. The symptoms of serotonin syndrome can include agitation, confusion, rapid heart rate, sweating, muscle rigidity, and in severe cases, can lead to life-threatening complications. Understanding that serotonin syndrome is fundamentally a state of heightened serotonin activity helps differentiate it from other conditions that might share overlapping symptoms.

In contrast, other options refer to either inappropriate responses in the context of serotonin syndrome or conditions unrelated directly to the excessive activity of serotonin itself. For instance, lowered blood pressure and increased risk of heart failure don't characterize this syndrome, as increased blood pressure is typically observed due to the sympathomimetic effects of elevated serotonin levels. Life-threatening cognitive impairment might occur but is not a defining feature of the syndrome—rather, the cognitive impairment is more accurately framed as a symptom of the overall excess serotonergic activity that defines the condition.