Two days after starting an antipsychotic medication, a patient suddenly develops a sustained, uncomfortable twisting of the neck to one side. Before revealing the answer: is this tardive dyskinesia?

No, this is more consistent with acute dystonia than with tardive dyskinesia. Tardive dyskinesia has a later, gradual onset after prolonged exposure and a repetitive, oral or facial movement quality; here, the sudden, sustained spasm arising within days of starting treatment, together with its dramatic presentation, points instead toward acute dystonia, which requires prompt recognition and treatment.