Movement Disorders Associated with Antipsychotic Medication
Antipsychotic medication is associated with a range of extrapyramidal movement disorders, which need to be recognised both because they cause distress and stigma in their own right and because some overlap with movement patterns that can also arise from the underlying psychiatric illness itself, independent of medication. Recognising these patterns, examining for them systematically before and during treatment, and eliciting their subjective as well as their outwardly visible components are all essential parts of good psychiatric care.
This has traditionally been organised into several recognised categories: akathisia (acute and chronic), acute dystonia, tardive dystonia, and acute and tardive dyskinesia, each with a different time course, clinical picture, and management approach, though it is worth noting that some of these movement patterns, such as tardive dyskinesia, are also seen in schizophrenia prior to any medication exposure.
Recognition features
- A range of distinct extrapyramidal patterns, each with its own characteristic time course and movement quality
- Some, like tardive dyskinesia, have both a medication-associated form and a form that can occur in schizophrenia independent of medication exposure
- Important subjective components, such as the inner restlessness and unease of akathisia, which may not be obvious from outward observation alone
- Significant potential for additional stigmatisation and social disability, particularly with visible, persistent movements such as tardive dyskinesia
Eliciting it at interview
- Carry out systematic examination for these movement disorders both before starting antipsychotic medication and at intervals during treatment, using clinical examination and validated rating scales where appropriate
- Always ask directly about subjective experience, particularly inner restlessness, tension, and unease, since these can be present and significant even when outward movement abnormality is subtle
- Take a careful history of movement symptoms present before any medication was started, since this distinguishes a purely medication-induced pattern from one with roots in the underlying illness itself
Distinguishing features
- Differs from catatonic and other primarily psychiatric motor signs in its specific association with antipsychotic exposure, timing relative to dose changes, and characteristic extrapyramidal quality, although careful differentiation is sometimes needed
- Akathisia, acute dystonia, and dyskinesia are each distinguished by their own characteristic timing and movement pattern, described in their own dedicated entries
- Management depends on which specific pattern is present, and may involve dose reduction, switching medication, or adding a specific treatment such as an anticholinergic agent, depending on the clinical picture and urgency
Common misconceptions
- That all antipsychotic-associated movement disorders look the same; each has a distinct time course and movement quality requiring separate recognition
- That these movement disorders are always obvious on observation; the subjective, inner components, particularly of akathisia, are easily missed unless specifically asked about
Related phenomena
Akathisia · Acute Dystonia · Tardive Dyskinesia
Practice this
A patient started on antipsychotic medication two weeks ago describes an inner urge to keep moving that he finds hard to resist, though on observation he only occasionally shifts his weight from foot to foot. What is the general category this presentation belongs to? · A patient recently started on an antipsychotic sits calmly during the interview and denies feeling unwell, but when asked directly whether he feels any inner restlessness or urge to move, he says yes, describing it as tension he can never quite shake and has not mentioned to anyone. Before revealing the answer: does the calm outward appearance rule out a movement disorder here? · A patient started on an antipsychotic ten days ago becomes stiff and restless, pacing the ward and unable to sit still, describing an unpleasant inner tension. A second patient, with no recent medication change, sits motionless for hours with a blank, deadpan expression, lively eyes, and a limb that remains fixed in whatever position it is placed. Are both of these best understood as antipsychotic-induced movement disorder? · You are reviewing a patient recently started on antipsychotic medication and want to screen for a subtle movement disorder that might not be obvious just from watching them. Which single question is most appropriate to ask? · Why is it important to take a careful history of movement symptoms present before any antipsychotic medication was started, rather than assuming any movement abnormality seen during treatment is medication-induced?
Illustration
A clinical team reviewing a patient recently started on antipsychotic medication uses a structured movement-disorder rating scale at each follow-up appointment, and specifically asks the patient at every visit whether they feel any inner restlessness or urge to move, catching a mild but distressing case of akathisia that would not otherwise have been obvious simply from watching the patient sit calmly in the consulting room.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 8, 'Motor Disorders'.