The Perfect Storm for Tardive Dyskinesia: An Aging Psychiatric Patient Population

Key Takeaways

• The world’s population is aging, and it is likely that mental healthcare professionals will increasingly have to provide care for older patients
• Older people are at high risk not just for tardive dyskinesia, but also for the complications and impairments that are associated with it
• Regular assessment for tardive dyskinesia is critically important in older people to prevent further complications

As a geropsychiatrist who treats patients with chronic psychiatric illnesses, including schizophrenia, bipolar disorder, and major depression, I often reflect on the significant demographic changes and evolution of available therapies that have a substantial impact on treatment planning. Perhaps the biggest shift driving increasing awareness and a need for care that considers the unique needs of older people with chronic psychiatric conditions is what has been referred to as “the silver tsunami.” This phrase very well describes the massive and rapid changes in population composition that are occurring not only within the United States, but globally.

With increased life expectancy and decreasing trends in birth rates, it is expected that between 2019 and 2050 in Europe and North America, the number of people older than 65 years of age will increase more rapidly than that of the population aged 25-64 years. Currently, the ratio between these age groups is approximately 1:3, and in 2050, it is expected to be 1:2. In parallel with this demographic trend, it is also expected that the numbers of people with chronic mental illness will increase both in absolute numbers and in line with the increased proportion of older people in the general population. With this changing demographic, it is likely that many healthcare professionals (HCPs) will be increasingly tasked with providing care for an older population in their practice. This is important because we can no longer pigeonhole the care of older people as a super-specialty or “niche” in the mental healthcare landscape.

Antipsychotic Use in the Older Population
Both schizophrenia and bipolar disorder are conditions that typically have onset in early adulthood and require long-term—or even lifetime—treatment. A cornerstone of treatment for patients with schizophrenia or bipolar disorder is the use of evidence-based antipsychotic medications. In the case of older-age patients with bipolar disorder, antipsychotic medication might be prescribed in tandem with other classes of medication such as anticonvulsants or mood stabilizers. A recent publication by an international team investigating treatments in older-age patients with bipolar disorder analyzed 16 pooled international research studies and found that close to half (46.6%) of older people with bipolar disorder were prescribed antipsychotic medications. The treatment of major depressive disorder, another common psychiatric condition affecting older people and often requiring long-term treatment, may also include the use of antipsychotic medications in adjunct with antidepressant medications. This is all to say that older patients with chronic psychiatric illnesses may be using antipsychotic agents for years and decades—creating the “perfect storm” for the development of tardive dyskinesia (TD).

An important potential drug-related complication of antipsychotics is the development of tardive syndromes, defined as persistent abnormal involuntary movement disorders. Of these, the most commonly noted is TD. The lifetime prevalence of TD in patients treated with antipsychotic drugs is between 16% and 50%, with higher rates seen among postmenopausal women. Among the risk factors for developing TD, the ones that are particularly relevant to older individuals include higher cumulative dose of antipsychotics (ie, longer exposure time, higher dosing) and older age. People with TD may be at increased risk for falls (if TD affects lower extremities or trunk). They also may experience stigma and social isolation, reduced quality of life, and functional impairment. These complications are already seen in the older population, and having TD can greatly increase their risks for falling and functional impairment.

Preventing and Managing TD
The best way to manage TD is to prevent TD. This includes appropriate—and sometimes sparing—use of antipsychotic medication, making sure to adjust the dosages so that they are appropriate for older individuals. In general, the antipsychotic dosage for older patients should almost always be lower than that for younger patients. Using lower dosages of antipsychotics not only minimizes TD risk, but can also minimize the risk of other adverse events such as drug-induced parkinsonism and sedation—both of which can also increase fall risk. For individuals with bipolar disorder and major depression, HCPs should consider therapies that do not increase the risk for TD, such as lithium or anticonvulsant agents, before initiating therapy with antipsychotic agents. 

The 2021 American Psychiatric Association Practice Guideline for the Treatment of Schizophrenia provides some useful recommendations on the assessment and treatment of individuals who must remain on antipsychotic medications for treatment. This includes ongoing evaluation for TD with a comprehensive assessment and physical examination, as well as the use of a structured evaluative tool such as the Abnormal Involuntary Movement Scale to establish a differential diagnosis of a movement condition—which can be particularly challenging when TD or suspected TD occurs in older people. It is important to assess for TD at every clinical visit and to gather input from family or support persons to complement the patient’s experience/report. For older patients, this also includes assessment of fall risk or gait problems that may affect functional independence.

The American Psychiatric Association (APA) guidelines provide information on 3 reversible VMAT2 inhibitors to treat TD: deutetrabenazine, tetrabenazine, and valbenazine. However, only deutetrabenazine and valbenazine have an FDA approval for TD; tetrabenazine is approved for Huntington’s chorea but may be used off-label for TD. These treatments differ on available formulations, dosing, bioavailability, metabolism, special considerations for patients with renal or hepatic impairment, food effect, and common adverse events. This may be particularly relevant for older patients given their generally greater propensity for drug-related adverse events. Although the APA guidelines note that VMAT2 inhibitors are recommended for moderate to severe TD symptoms, the guidelines do not specifically provide cutoff thresholds for when VMAT2 inhibitors should be used. In older people with TD, clinical care planning needs to consider factors such as patient awareness of movements, fall risk, functional state, available supports in the home, and medical comorbidities.

The bottom line is that the aging population is at increased risk for TD, and HCPs from all “niches” must be familiar with the risk factors, prevention tactics, and management strategies in order to optimize patient care.