Ask an Expert: Dr. Andrew Howard Discusses Problematic Anxiety in People with Parkinson’s
Dr. Andrew Howard, MD, FRCPC is currently a Clinical Associate Professor in the Department of Psychiatry at the University of British Columbia (UBC), and a consultant neuropsychiatrist and clinical researcher involved with movement disorder patients at the Pacific Parkinson's Research Centre and the Centre for Huntington Disease at UBC. In 2021, Dr. Howard spoke at Parkinson Society BC’s Annual General Meeting on the manifestations and complications of problematic anxiety in Parkinson’s disease.
How common is anxiety in people with Parkinson’s disease?
Anxiety is one of the most common psychiatric symptoms experienced by people with Parkinson’s disease (PD). At any given point in time, one-third of people with PD are experiencing anxiety; this increases to 50% over the entire course of illness.
What are the common types and expressions of anxiety in Parkinson’s disease?
Common types of anxiety in Parkinson’s disease include panic attacks (unrelated to the timing of medication), episodic anxiety (which may be associated with the wearing off of dopaminergic drugs), persistent generalized anxiety, social anxiety and fear of embarrassment, and phobias (such as a fear of freezing, falling, or choking). Expressions of anxiety in PD frequently manifest as tension, restlessness, irritability, slow thinking, and/or poor concentration.
What are the risk factors for developing anxiety in PD?
Individuals with a personal or family history of anxiety and other related psychiatric conditions are at greater risk of developing an anxiety disorder. PD-specific risk factors include a younger age of onset, faster rate of disease progression, greater disease severity, autonomic symptoms (such as difficulty regulating body temperature and heart rate), and REM sleep behaviour disorder, a common sleep disturbance experienced by people with Parkinson’s. Motor fluctuations, such as end-of-dose effects, difficulty with medication kicking in, dyskinesia, and freezing episodes may also directly cause anxiety disorders. Individuals with PD who have less social support are at greater risk of developing an anxiety disorder. Furthermore, an avoidant personality, a tendency towards avoiding fear-provoking situations or activities, increases susceptibility to anxiety. This is because avoidance feeds fear and is arguably the most important disease-modifying variable in all anxiety-based conditions.
Is anxiety directly caused by Parkinson’s, or is it a response to a loss of motor control?
Traditionally, anxiety has been viewed as a reaction to the physical manifestations of Parkinson’s, as well as the difficulty of living with a progressive, degenerative condition. However, the latest research is challenging this assumption. There is evidence indicating that the neurodegeneration caused by PD not only affects motor circuits of the brain, but also areas involved in emotional processing, likely directly causing anxiety.
A study that utilized neuroimaging to examine the brains of individuals with anxiety and PD, noted an overlap between areas of the brain traditionally associated with fear and those impacted by Parkinson’s. It also revealed a greater disruption of serotonin pathways. Serotonin is often known as the “happy chemical”; its depletion directly causes anxiety. Furthermore, when examined clinically, patients with an abrupt onset of motor fluctuations frequently reported increasing anxiety prior to the onset of the motor changes. Many also often reported anxiety in the early stage of the illness, before being diagnosed with Parkinson’s. This evidence points to anxiety as a symptom of the disease, and less so as a reaction to the loss of motor control.
On the contrary, there is also evidence that loss of motor control may cause anxiety in some individuals with Parkinson’s. A study demonstrated that PD patients with higher anxiety had decreased dopamine uptake at diagnosis, implying that they would be more susceptible to shifts in dopamine from the beginning of the disease, even before starting medication. Another study compared a Levodopa infusion to a placebo. It was found that the Levodopa infusion assisted with mood elevation and anxiety reduction. This indicates that for certain people with PD, managing Parkinson’s symptoms may be effective at reducing anxiety.
It appears that whether anxiety is a symptom of neurodegeneration or a response to living with PD depends on the timing of its onset, and is best assessed by medical professionals involved in the management of the individual’s disease. Determining the timing of its onset is important to ensure targeted, appropriate treatment.
What are some of the obstacles in treating anxiety in Parkinson’s?
Despite its prevalence in people with PD, and relative ease for effective treatment, anxiety often goes untreated. There remains an assumption between healthcare professionals, carepartners, and patients that anxiety is always a byproduct of chronic disability, and that if patients are able to overcome the challenges they face as a result of their Parkinson’s, the anxiety will resolve. This is a bias that we need to correct, as it does not consider the effect of neurodegeneration on the development of anxiety disorders.
In combination with this bias, the placebo effect commonly seen in the PD population makes it difficult to show the impact of a medication or intervention. Because this effect requires studies to be very large, there continues to be minimal research support and scientific evidence for proper assessment and management of anxiety in PD. This further reinforces the bias that the individual should manage anxiety on their own, as up until recently there have been few evidence-based guidelines for professionals and patients.
What therapeutic options exist to treat anxiety in Parkinson’s?
Cognitive behavioural therapy (CBT) is recognized as the gold standard in treating anxiety, in combination with anxiety-reducing medications. CBT helps individuals limit or diminish avoidance and slowly do more of what they fear, rather than being controlled by what they imagine will be the worst outcome. CBT is most effective when carepartners are involved, as learning it helps them to better support their loved one. The evidence for CBT’s effectiveness for people with PD is encouraging. A study of 48 Parkinson’s patients, given either 10 weekly sessions of CBT or just clinically monitored with no exposure to CBT, showed that all subjects improved, demonstrating the common placebo effect amongst people with PD. However, those receiving CBT showed a reduction of 10 points on the Parkinson Anxiety Scale, a frequently used anxiety assessment tool, compared to just five points in the control group.
There are also alternative therapies available to treat anxiety, such as mindfulness and yoga. While there is limited data supporting the effectiveness of these therapies specifically for treating anxiety in people with Parkinson’s, they are generally regarded as helpful for both physical and mental wellbeing.
What medications and medical options can help treat anxiety in Parkinson’s?
To help manage anxiety, it is crucial that PD medication be optimized to minimize ‘off’ periods. This may be done with the use extended-release medications, enzyme inhibitors, and dopamine agonist patches. It is important to note that anti-parkinsonian agents, such as Sinemet®, do not always improve anxiety and should not be relied upon for this purpose. Individuals will often increase their Sinemet® in response to motor fluctuations caused by anxiety, which can actually result in increased anxiety due to greater shifts in dopamine levels. Furthermore, these drugs may provoke anxiety when started initially in up to 20% of patients.
Many psychiatric medication options exist for treating anxiety in PD, particularly high dose SSRIs (selective serotonin reuptake inhibitors) or SNRIs (serotonin–norepinephrine reuptake inhibitors). If CBT in combination with SSRI/SNRI treatment fails, antipsychotic medications may be a good next choice. This class of drugs is the most effective anti-anxiety medication prescribed by psychiatrists, but typically worsens the motor symptoms of PD. However, some antipsychotic drugs, such as quetiapine and clozapine, are effective at managing anxiety without worsening motor symptoms.
The use of benzodiazepines is typically discouraged for people with Parkinson’s. Such drugs may cause sedation, cognitive impairment, and balance issues, as well as tolerance and dependency. These side effects, should they occur, are especially problematic for people with PD. However, early in the course of anxiety symptoms in PD, benzodiazepines can help individuals regain a sense of control, reduce anxiety, and limit worsening of avoidance behaviour.
Currently, there are other treatment options showing promise, including the use of cannabinoids and probiotics. More research needs to be conducted to truly assess their effectiveness.
Although anxiety can sometimes lead to feeling overwhelmed, know that you are not alone if you are experiencing it. There are many treatment options that can be explored. Speak to your doctor about what may work best for you.
This content was published in the Spring 2022 edition of our quarterly magazine, Viewpoints. The content was accurate as of this publication date.