**Question:** Extrapyramidal side effects of antipsychotics -

A. Dyskinesias
B. Paraesthesia
C. Anxiety
D. Insomnia

**Core Concept:** Extrapyramidal side effects (EPS) are a group of symptoms that occur due to the blockade of dopamine D2 receptors in extrapyramidal pathways, mainly in the basal ganglia. These symptoms can be caused by antipsychotic medications, which are primarily used to treat schizophrenia and other psychiatric disorders.

**Why the Correct Answer is Right:** Extrapyramidal side effects are primarily caused by the blockade of dopamine D2 receptors in extrapyramidal pathways, which are part of the basal ganglia, a region in the brain involved in motor control and coordination. The correct answer, A - Dyskinesias, is a specific type of EPS characterized by involuntary, uncontrollable muscle contractions that can manifest as chorea (random), dystonia (contracted), or parkinsonism (rigidity and tremors).

**Why Each Wrong Option is Incorrect:**

**Option A (Paraesthesia):** Paraesthesia is a sensation of tingling, prickling, or numbness, often unrelated to motor symptoms and not directly caused by antipsychotic medications. It is unrelated to the blockade of dopamine D2 receptors in extrapyramidal pathways.

**Option B (Anxiety):** Although antipsychotics may cause some degree of sedation and mood changes, anxiety is not a direct consequence of extrapyramidal side effects caused by dopamine D2 receptor blockade in the basal ganglia.

**Option C (Dyskinesia):** While dyskinesias (option A) are indeed a specific type of extrapyramidal side effect, paraesthesia (option A) is a distinct symptom unrelated to extrapyramidal side effects.

**Option D (Insomnia):** Insomnia is a common side effect of antipsychotics but is not directly caused by dopamine D2 receptor blockade in the basal ganglia, which leads to extrapyramidal side effects.

**Clinical Pearl:** Understanding the core concept of extrapyramidal side effects and distinguishing between specific symptoms like dyskinesias and unrelated symptoms like anxiety and paraesthesia is essential when reviewing side effects of antipsychotic medications. This knowledge helps differentiate between drug-induced symptoms and clinical manifestations of neurotransmitter imbalances, such as anxiety in a patient with a psychiatric disorder.