From the Research
There are no specific laboratory tests to evaluate tardive dyskinesia (TD), and diagnosis is primarily clinical, based on observation of abnormal involuntary movements and a history of antipsychotic medication use. The evaluation of TD involves using validated clinical rating scales such as the Abnormal Involuntary Movement Scale (AIMS) to assess and monitor the severity of movements, as recommended by a recent study published in The Journal of clinical psychiatry 1. While blood tests may be ordered to rule out other conditions that can cause similar movements, such as thyroid dysfunction, liver disease, or Wilson's disease, these are not diagnostic for TD itself.
Some key points to consider in the evaluation of TD include:
- The use of clinical rating scales like AIMS to assess the severity of movements, as discussed in a study published in Hospital & community psychiatry 2
- The importance of direct observation of the patient for abnormal movements in different body regions
- The potential use of neuroimaging studies like MRI or CT scans to exclude structural brain lesions as a cause of the movements, although these do not confirm TD
- The reliance on the clinician's assessment of the characteristic movement patterns in the context of medication exposure, typically after at least three months of antipsychotic treatment or within one month of discontinuation in older patients, as noted in a study published in Parkinsonism & related disorders 3
It's also worth noting that the treatment of TD may involve the use of vesicular monoamine transporter 2 inhibitors, such as valbenazine and deutetrabenazine, which have been shown to be effective in decreasing AIMS scores and are well tolerated, as demonstrated in a study published in American journal of health-system pharmacy 4. However, the diagnosis and evaluation of TD remain primarily clinical, and laboratory tests play a limited role in this process.