Beyond the Side Effect: Understanding and Addressing Tardive Dyskinesia

Hello dear colleagues, welcome to this podcast. We're going to be talking about Beyond the Side Effects, Understanding and Addressing Tardive Dyskinesia. Now the focus here is going to be for us healthcare providers to appreciate the persistence and pathophysiology of tardive dyskinesia and how do we distinguish it from common medication side effects? Because as we well know, our antipsychotics, be they typical or atypicals, can cause a variety of movement difficulties that can be easily confused with tardive dyskinesia. So my task today is to look beyond the side effect and understand and address tardive dyskinesia.

Okay, so the big challenge here is that many clinicians do perceive tardive dyskinesia as just another side effect of the medication, rather than what it is, a chronic and very often, in fact, in the majority of patients, an irreversible disorder that requires proactive management from us. So perhaps we should deal with this issue quite directly and head on by stating a few things about tardive dyskinesia, that it is actually quite common. It's in fact also quite commonly missed by us, not because we can't see the patient's abnormal movements on most occasions, it's because we often think of it as a different condition. And the most common incorrect diagnosis we apply to it is often what we in psychiatry often call it EPS. EPS as if EPS is a diagnostic category. EPS has become psychiatry's one of its greatest wastebasket diagnosis. And we will have to be very careful not to apply it incorrectly and injudiciously for obvious reasons, right? Because patients can be misdiagnosed, mistreated, and mistreatment can lead to further problems for the patients at a number of levels.

Let's for a second reestablish what we do know about tardive dyskinesia. So tardive dyskinesia as per DSM-5 is a condition caused by exposure to a dopamine blocking agent, which in your and my specialty typically means exposure to atypicals or typical antipsychotics for a variety of disorders such as schizophrenia, bipolar disorder, unipolar depression, and a whole host of other conditions, including the common use of these medications in cognitive difficulties, in developmental difficulties. So there are a number of patients. In fact, the numbers appear to be in the 700,000 plus individuals in America who have tardive dyskinesia, and only about 15 % of them are thought to have receive the right diagnosis. So the question that naturally follows, we in the healthcare field are so tuned into our patients' needs. Why are we having a difficult time looking beyond the side effect to looking at it more as an often irreversible life-impairing condition? I believe the problem starts at the very beginning from our training.

You and I classically have not received a great deal of training in Tardive dyskinesia in our various professional training schools. If you look at someone my age, I hardly got a single conversation about it in five years of training. So that's problem number one. The problem number two was until quite recently, just about eight, nine some years ago, we did not even have treatment options.

So psychiatry thought, what's the whole point of making a diagnosis if I can't treat it? Well, by now we know that is no longer an issue. But the third is we have not been trained to differentiate the most common erroneous diagnosis that gets applied to tardive dyskinesia, which is of course drug induced Parkinsonism. So we'll be talking about that momentarily.

But if you don't mind, let's just remember that the pathophysiology of drug-induced Parkinsonism and that of tardive dyskinesia are completely different. In fact, they're so different, they can be thought of as the sunrise and the sunset in a day, quite opposite to each other. So tardive dyskinesia is caused by an upregulation of D2 receptors while drug-induced Parkinsonism is caused by the downregulation of those receptors. So the symptoms are very different.

We also know that tardive dyskinesia is a disorder of excess movements, right? Excess movements in muscles that are voluntary in nature. But drug-induced Parkinsonism is the opposite. It's too little. That's why we talk about a shuffling gait, mask-like facies and you can also have a rhythmic tremor with it. There are considerable challenges in not making the right diagnosis and I will highlight two for you in the next couple of minutes. And my goal is really not to blame or obviously shame psychiatry, but to encourage those of us in the world of psychiatry to appreciate that this misdiagnosis or delayed diagnosis comes with huge challenges for our patients. Here's the first challenge.

So let's just play out a scenario. So if I do have a patient with tardive dyskinesia, but I've applied the diagnosis of drug-induced Parkinsonism or quote unquote EPS, then the odds are quite high this patient would receive an anticholinergic agent and of course the classic one is benestropine, right? We use that sadly way too frequently in psychiatry. And when one does that, it in fact not only delays the diagnosis, that would be bad enough, right? But the problem is applying an anticholinergic can in fact make tardive dyskinesia biologically and symptomatically much worse. Yes dear colleagues, indeed that much worse.

So it's not just a matter of gosh, I'll get to the right diagnosis in time. An incorrect diagnosis can lead to profound challenges and the emotional burden. By now, my research and my colleagues' research that you most likely have laid your eyes on has demonstrated one crystal clear fact. The emotional burden, the physical burden, the social burden, the biopsychosocial burden of tardive dyskinesia is substantial, particularly in a population that is already very vulnerable to challenges.

So the task we have, my dear colleagues, is to identify high-risk patients and to look for early warning signs. Let's spend a minute talking about both of these two sections. First of all, who's at high risk? But perhaps the question we could also ask in reverses, who is absolutely not at risk? And that's an easy question to answer because the answer is nobody. In other words, everybody, everybody, no matter what your age, your diagnosis, whatever. If they have received a D2 blocking agent, they could develop tardive dyskinesia. But who's at high risk? And here we do have some information. The female gender, older age, the presence of a mood disorder, and of course, the concurrent or past use of an anticholinergic. All of these collude together to create an increased risk of development of tardive dyskinesia. But I should hasten to add, if you're looking for one group of patients who absolutely don't develop tardive dyskinesia and we don't need to worry about them, I'm afraid that patient has not yet been born.

So we should keep a high index of suspicion with everybody, of course, with certain patients like I've described before, more so of a worry, but we do have to think about everybody. And then finally, let's come to perhaps appreciating how does this task of looking for the right diagnosis ultimately help the patient? Well, here's how it can and does help a patient. Once we have the right diagnosis, we could eliminate medications that are causing the patient to have further challenges.

So for example, an anticholinergic could be gradually tapered and stopped. And of course, an appropriate medication for a patient who has tardive dyskinesia, assuming it's mild, especially if they have impairment, they could then get one of the two FDA approved treatment options for tardive dyskinesia, valbenazine or dutetrabenazine. And needless to say, once someone knows what's wrong with them, it's just easier for them and their family to deal with the challenge.

So in conclusion, as you and I look beyond the side effect and do our very best to understand and address tardive dyskinesia, what we find is understanding the pathophysiology of tardive dyskinesia and distinguishing it from other common medication side effects ultimately leads the patient towards the right diagnosis, the right treatment, and obviously as a result of that, to better quality of life and functionality in life. Well, thank you very much, dear colleagues, for allowing me to talk a little bit about this important topic, and I look forward to talking with you on another topic down the road. Goodbye for now.