Which of the following is NOT a manifestation of Lithium toxicity?

Lithium toxicity is known to produce several specific symptoms, often as a result of elevated lithium levels in the blood. Common manifestations include sedation, coarse hand tremors, and various cardiac manifestations like ECG changes. Sedation can occur as the central nervous system is affected, resulting in lethargy or drowsiness. Coarse hand tremors are a classic sign of lithium toxicity, indicating that the neuromuscular system is impacted. ECG changes can also be seen, as lithium can affect cardiac conduction pathways.

In this context, hyperactivity is not typically associated with lithium toxicity. In fact, it tends to be the opposite; individuals experiencing toxicity may show signs of lethargy rather than increased energy levels or hyperactivity. Thus, when identifying manifestations of lithium toxicity, hyperactivity does not align with the expected symptoms, marking it as the correct response to the question.