**Question:** A 30-year-old manic patient was prescribed haloperidol 3 months back. For the last two days, he has become restless and kept pacing in the room for a day. On examination, he was found to have tremors of hand. He is most likely to be suffering from:

**Core Concept:** Haloperidol is an antipsychotic drug that acts as an antagonist at dopamine D2 receptors, primarily used to treat schizophrenia and bipolar disorders. Dopamine D2 receptor antagonism can lead to extrapyramidal side effects (EPS), such as tremors, rigidity, and parkinsonism.

**Why the Correct Answer is Right:** The patient's symptoms of restlessness, pacing, and hand tremors are consistent with extrapyramidal side effects (EPS) caused by haloperidol treatment. The duration of treatment (3 months) is also a risk factor for the development of these side effects.

**Why Each Wrong Option is Incorrect:**

A. **Tardive dyskinesia (TD)** is a delayed onset EPS that typically presents with involuntary limb movements, not tremors or restlessness.
B. **Drug withdrawal** symptoms are unlikely, as the patient has been on haloperidol treatment for 3 months.
C. **Hypersomnia** and **neuroleptic malignant syndrome** (NMS) are not mentioned in the question and are not relevant to the presented symptoms.
D. **Haloperidol-induced hypokinesia** may lead to rigidity and akinesia, not tremors and restlessness.

**Clinical Pearl:** Extrapyramidal side effects (EPS) can be managed with medications like benzodiazepines, anticholinergics, or reducing the antipsychotic dose. In this case, haloperidol should be tapered gradually and supportive therapy should be considered.