Tardive dyskinesia
Meaning of tardive dyskinesia: For the purposes of this Statement of Principles, tardive dyskinesia: (a) means a movement disorder which meets the following criteria (derived from DSM-5-TR): (i) abnormal, involuntary movements of the tongue, jaw, trunk, or extremities that develop in association with the use of medications that block postsynaptic dopamine receptors; (ii) the movements are present over a period of at least 4 weeks; (iii) there must be a history of use of the offending agent for at least 3 months in individuals <60 years of age or at least 1 month in individuals age 60 years or older; and (iv) symptoms and signs develop during medication use or within 4 weeks of withdrawal from an oral agent or within 8 weeks of withdrawal of a long-acting injectable agent; and (b) excludes: (i) medication-induced parkinsonism, acute dystonia and acute akathisia; (ii) dyskinesia due to l-dopa or bromocriptine; (iii) spontaneous dyskinesia; (iv) neurological diseases including Huntington disease, Wilson disease, Sydenham chorea, systemic lupus erythematosus, and heavy metal poisoning.
Reasonable Hypothesis (RH) — Statement of Principles No. 78 of 2023
At least one of the following factors must as a minimum exist before it can be said that a reasonable hypothesis has been raised connecting tardive dyskinesia or death from tardive dyskinesia with the circumstances of a person's relevant service:
- (1)taking an antipsychotic medication for least 3 continuous months for persons under 60 years of age or at least 1 month for persons aged 60 years or older, before the clinical onset of tardive dyskinesia and where the symptoms and signs of tardive dyskinesia develop during antipsychotic medication use or within 4 weeks of withdrawal from an oral antipsychotic medication or within 8 weeks of withdrawal from a long-acting injectable antipsychotic medication;
- (2)taking antiemetic drug metoclopramide, domoperidone, droperidol, or prochlorperazine, or the anxiety drug buspirone for least 3 continuous months for persons under 60 years of age or at least 1 month for persons aged 60 years or older, before the clinical onset of tardive dyskinesia and where the symptoms and signs of tardive dyskinesia develop during antiemetic medication use or within 4 weeks of withdrawal from an antiemetic medication;
- (3)taking anticholinergic medications that cannot be ceased or substituted at the time of the clinical worsening of tardive dyskinesia;
- (4)inability to obtain appropriate clinical management for tardive dyskinesia before the clinical worsening of tardive dyskinesia;
Aggravation-only factors: the factors in subsections 8(3) and 8(4) apply only to material contribution to, or aggravation of, the condition where it was suffered or contracted before or during (but did not arise out of) the person’s relevant service.
Balance of Probabilities (BoP) — Statement of Principles No. 79 of 2023
3 factors
At least one of the following factors must exist before it can be said that, on the balance of probabilities, tardive dyskinesia or death from tardive dyskinesia is connected with the circumstances of a person's relevant service:
- (1)taking an antipsychotic medication for least 3 continuous months for persons under 60 years of age or at least 1 month for persons aged 60 years or older, before the clinical onset of tardive dyskinesia and where the symptoms and signs of tardive dyskinesia develop during antipsychotic medication use or within 4 weeks of withdrawal from an oral antipsychotic medication or within 8 weeks of withdrawal from a long-acting injectable antipsychotic medication;
- (2)taking antiemetic drug metoclopramide, domoperidone, droperidol, or prochlorperazine, or the anxiety drug buspirone for least 3 continuous months for persons under 60 years of age or at least 1 month in subjects aged 60 years or older, before the clinical onset of tardive dyskinesia and where the symptoms and signs of tardive dyskinesia develop during antiemetic medication use or within 4 weeks of withdrawal from an antiemetic medication;
- (3)inability to obtain appropriate clinical management for tardive dyskinesia before the clinical worsening of tardive dyskinesia;
Aggravation-only factors: the factors in subsection 8(3) apply only to material contribution to, or aggravation of, the condition where it was suffered or contracted before or during (but did not arise out of) the person’s relevant service.
