Healthy Living

Low Adherence to Antidepressants May Increase Mortality in Parkinson's Patients

Low Adherence to Antidepressants May Increase Mortality in Parkinson's Patients

Parkinson’s disease, a neurological condition that affects a person’s body movements,  has been affecting thousands of people’s physical and mental abilities. According to the National Parkinson Foundation, Parkinson’s disease itself is not fatal. However, complications that are brought by Parkinson’s have made the disease as the 14th top cause of death in the US.

Thinking difficulties, swallowing problems, sleep problems and disorders, bladder problems, constipation, emotional changes, and depression are some of the problems that accompany Parkinson’s disease.

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Some Background on Depression and Anxiety

Depression is characterized by the feeling of sadness and moodiness for long periods of time. This affects how a person treats and sees himself or herself. Having depression may cause one to lose interest in working, socializing, and taking care of oneself. On the other hand, anxiety is characterized by the feeling of being uncomfortable or anxious. Naturally, a person feels anxious if he or she is under pressure. However, other people feel anxious without certain reasons. Even if they succeed in undergoing a stressful event, this uncomfortable feeling remains. People with anxiety may experience hot and cold flushes, fast heart rate, chest tightening, snowballing worries, and obsessive thinking and compulsive behavior.
The people around patients with Parkinson’s disease must be able to detect their depression and anxiety. Thus, if symptoms like lack of interest, fatigue, pessimism, being irritable or moody persist, they should start doing something to support the patients.

According to Parkinson’s NSW, anxiety and depression are considered to affect half of all people with Parkinson’s disease while 10-20% have major depressive disorder or also known as MDD. Patients with this disease usually feel down and anxious about having Parkinson’s. They tend to worry about the consequences that this kind of disease may bring into their lives. Aside from that, research also shows that Parkinson’s disease may bring some changes in a patient’s brain. This may result in having a greater risk of depression.

Beyondblue mentioned that it is often that the symptoms of Parkinson's and depression overlap; this makes the diagnosis difficult. However, they noted that it is still important to identify and treat these mental health problems. If these are untreated, these may worsen a patient’s feeling of isolation and trigger for some problems to occur in relationships. Additionally, anxiety and depression may also worsen one’s physical symptoms. Like for example, anxiety is said to exacerbate gait problems, more uncontrolled movements, and freezing.
Researchers also believe that depression and anxiety may be due to the hidden changes in the brain chemistry and circuitry that are brought by Parkinson’s disease itself. As a matter of fact, depression and anxiety may exist even before motor symptoms.

The pathways that create dopamine in the brain also generate the hormonal neurotransmitter serotonin. Unfortunately, these are affected by the disease itself.  Serotonin is a kind of chemical nerve that cells produce. This is tasked to regulate one’s mood, appetite, and sleep. Thus, having lower levels of serotonin may lead Parkinson’s disease patients to depression and anxiety.

In April 2012, the first major clinical study of antidepressants for people with Parkinson’s disease was conducted. The Study of Antidepressants in Parkinson’s Disease or SAD-PD found that some of the antidepressants can ease Parkinson’s patients’ depression without affecting the motor symptoms.

The Michael J. Fox Foundation stated that depression can be seriously destructive. This affects the patient’s motivation to socialize, exercise, and taking care of oneself. Thus, taking medications, therapy, and other guidance from the health expert is a must. Through these, PD patients will have great benefits both mentally and physically.

What Does the New Study Say?

A 4-year follow-up study was conducted to examine the relationship of adherence to antidepressants and Parkinson’s disease’ mortality. This study was conducted by the Clalit Health Service, which is a well-known healthcare provider in Israel. It was then published in the journal Parkinsonism and Related Disorders.

Between 2008 and 2014, 8,553 Parkinson’s patients who bought antidepressants  were closely monitored for four years. On the other hand, the researchers set four classifications of adherence: non-adherence, poor adherence, moderate adherence, and good adherence. Adherence was assessed as a ratio between dispensed and prescribed durations. Thus, this means that non-adherence was less than 20% (1,566 patients), poor adherence was 20-50% (1,184 patients), moderate adherence was  50-80% (1,584 patients), and lastly, good adherence was higher than 80% (4,2019 patients).

The resulted unadjusted mortality rates were 20.4% for non-adherent, 25.1% for poorly adherent, 23.4% for moderately adherent, and 25.6% for well adherent to antidepressants. However, when these were adjusted due to some demographic and clinical variables, it turned out that the non-adherent patients had a considerably higher mortality rate together with the poorly adherents ones. The non-adherence group had a higher risk of death of 43% while the poor adherence group had 26%. Not just that, it was also found out that men had a higher risk of 49% as compared to women.

Another thing that researchers looked into was the comorbidities or known as the simultaneously existing conditions and their relationship with mortality. They discovered that when patients have three to four comorbidities, they have 30% greater risk of death as compared to those who don’t have or have only two comorbidities. On the other hand, patients with five or more comorbidities have 78% risk of death.

It is evident that antidepressants have valuable benefits for patients with Parkinson’s disease. However, the benefits highly depend on patients’ adherence to antidepressants. Parkinson’s News Today served patients with MDD or major depressive disorder as an example. If these patients don’t take antidepressants as prescribed, then they are said to have more emergency room visits, higher hospitalization rates, and greater severity of depression according to the study.

Truly, adherence to antidepressants varies from patient to patient with Parkinson’s disease. Yet, this adherence is still often low. This low adherence is associated with poorer clinical outcomes and higher-related costs.

These show that neurologists, psychiatrists, and primary care physicians should consider the use of antidepressants for their Parkinson’s patients as pivotal. Since poor adherence to antidepressants is clearly associated with all-cause mortality in Parkinson’s Disease patients.


The study shows a clear relationship between Parkinson’s disease and depression. These complications may be more harmful than Parkinson’s itself. Thus, it is also apparent to pay attention to a patient’s emotions and feelings while having this disease. For medical experts like neurologists and psychiatrists, they may be able to find some ways to on how to promote adherence to antidepressants to their patients. Aside from that, choosing the best and most effective antidepressant for their patients is also a substantial task for them. 

As for patients’ side, it may be difficult to cope with depression and anxiety at first, but taking small steps is essential. A great support system from family, friends, and even from their own personal health care providers is highly needed. Moreover, there are lots of ways on how to treat depression and anxiety aside from maintaining antidepressants; this depends on what kind of depression and anxiety a patient has. The most important thing to consider is the patient’s willingness to help himself or herself.