Which symptom is characteristic of tardive dyskinesia?

• A. Lip smacking
• B. Resting tremor
• C. Akathisia
• D. Dystonia

Answer: (A)

Tardive dyskinesia is marked by involuntary, repetitive movements that often involve the face and mouth after long-term dopamine D2 receptor blockade from antipsychotics. Lip smacking is a classic example of these orofacial dyskinesias, and you’ll often see grimacing, puckering, or tongue thrusts as well. This pattern—repetitive, purposeless movements of the lips and jaw—is what clinicians use as a hallmark of TD.

Resting tremor points to Parkinsonism, which features a tremor seen when the limb is at rest and is not the predominant pattern of TD. Akathisia involves inner restlessness with an urge to move, not the involuntary facial movements characteristic of TD. Dystonia involves sustained, sometimes painful muscle contractions causing abnormal postures, which is a different movement disorder and can occur acutely, not the typical tardive lip movements.