Are Tremors Considered Part of Tardive Dyskinesia?
Tremors are NOT typically considered a classic manifestation of tardive dyskinesia (TD), but a distinct entity called "tardive tremor" can occur as a separate tardive syndrome following chronic dopamine receptor blocking agent exposure.
Understanding the Clinical Distinction
The classic presentation of TD does not include tremor as a primary feature. According to the American Academy of Child and Adolescent Psychiatry, tardive dyskinesia is characterized by rapid involuntary facial movements (e.g., blinking, grimacing, chewing, or tongue movements) and extremity or truncal movements 1. This definition focuses on choreiform and athetoid movements, not tremor 1.
Tardive Tremor as a Separate Entity
However, tremor can occur as part of the broader spectrum of tardive syndromes:
Tardive tremor is a distinct movement disorder that develops after chronic neuroleptic exposure, characterized by oscillatory movements with a frequency of 3-5 Hz, most prominent during posture maintenance but also present at rest and during goal-directed movements 2
This tremor differs fundamentally from the resting tremor seen in drug-induced parkinsonism 3
Tardive tremor typically occurs alongside other tardive movement disorders including akathisia, chorea, dystonia, myoclonus, and stereotypy 2
Important Clinical Differentiation
When evaluating tremor in patients on antipsychotics, you must distinguish between:
Drug-induced Parkinsonism: Presents with bradykinesia, tremors (typically resting), and rigidity—this is an acute/subacute extrapyramidal side effect, not TD 1. Anticholinergic agents like benztropine can treat parkinsonian tremor 1
Tardive tremor: Persists after neuroleptic withdrawal, worsens with withdrawal, and may improve with dopamine-depleting agents like tetrabenazine 2
Classic TD: Involves choreiform/athetoid movements without tremor as a primary feature 1
Practical Clinical Approach
If a patient develops tremor while on antipsychotics, first consider drug-induced parkinsonism rather than TD, especially if it occurs early in treatment 1
Parkinsonism (including tremor) can develop within the first two weeks of starting or increasing antipsychotic doses 4
The term "tardive syndrome" serves as an umbrella term for all persistent hyperkinetic, hypokinetic, and sensory phenomenologies from chronic dopamine receptor blocking agent exposure, with TD being one specific type 3
Key Caveat
Some older literature may inappropriately lump various movement disorders together under "TD," but modern nosology recognizes these as distinct entities 3. Parkinsonism (with tremor) should be differentiated from TD, even though elements of both may occur together 5.