Introduction

As a child, I grew up in a culture where saying ‘thank you ‘ was a metric of responsible parenting. In the Irish language we say ‘go raibh maith agat’ for thank you which roughly translates into ‘may you have good’.

Some decades later and despite living in three continents, I am still hard-wired to thank everyone and everything. I keep a set of Thank You cards in my desk at work and not a week goes by without one of those little cards being sent on an errand to thank someone (Princess Diana was also a big fan of Thank You notes).

Gratitude has been hijacked by management, leadership and personal development trends in the last few years.

More recently, I notice attempts at the ‘medicalization’ of gratitude. The topic of gratitude is popping up at medical conferences and in our journals. We, as doctors, are encouraged to practice gratitude and we are also encouraged to recommend that our patients practice gratitude.

Even though I am a staunch advocate of gratitude, I draw the line at recommending it to my patients unless there is an evidence base to support it. There is a very definite line between personal beliefs and professionalism and I try to separate the two.

Is gratitude just a nice thing to do (as my granny taught me) or does it have therapeutic benefits?

What Is Gratitude?

Gratitude is generally defined as being thankful or showing appreciation.

Dr Robert Emmons has defined two stages of gratitude:

  1. Recognising good things in your life
  2. Acknowledging that the source of these goods things is outside of oneself.

Straight away I see a difference between the usual concept of gratitude and ‘medical gratitude’. I have been to a number of medical lectures on the therapeutic value of gratitude (hard to avoid them these days). These lectures take a slightly different approach to the definition of gratitude. These lectures advocate appreciation for not just good things but also for things that are considered to be ‘bad’ e.g. sickness, loss or pain. Medical gratitude does have some parallels to general gratitude in that it also emphasizes the fact that the source of illness, pain, loss is outside of us.

Gratitude is really trending right now on social media. The #hashtag ‘gratitude’ has over 11 million posts. Gratitude is also a very popular topic for TedTalks. The most popular TedTalk on gratitude has over 5.2 million views. Not bad for one video.

There are over 20,000 gratitude products for sale on Amazon which includes journals, books, diaries, decals, mugs and thank you cards.

Is There Any Research?

There are 1,053 publications relating to gratitude which includes 48 clinical trials. This is not a huge body of research for such a popular topic. To put things into context, there are over 5,000 publications relating to meditation which includes over 800 clinical trials.

High-Level Overview of Gratitude

Not only are we seeing the medicalization of gratitude, we are also seeing high-tech medical technology being used to understand the physiology and neuroscience of gratitude.

Nowadays we can use functional MRI scanning to get real-time images of which parts of the brain are activated during particular activities or emotions.

Investigators at University of Southern California Los Angeles monitored brain activity on functional MRI while inducing feelings of gratitude in study participants (1).

Initially, 26 students were enrolled in the study but 3 students were excluded due to technical issues. All study participants were right-handed and none had close contact with Holocaust survivors (for reasons that will become clear).

The stimuli used to elicit gratitude were drawn from stories of survivors of the Holocaust, as many survivors report being sheltered by strangers or receiving lifesaving food and clothing, and having strong feelings of gratitude for such gifts.

Study participants rated how grateful they felt while imagining receiving the gifts. The results revealed that ratings of gratitude correlated with brain activity in the anterior cingulate cortex and medial prefrontal cortex. This gives us insight into where gratitude comes from.

One key limitation of this study is the fact that it is assumed that the areas of the brain recruited in this gratitude simulation study would correlate with the areas of the brain responsible for the emotions of gratitude in real life. However, it is possible that imagined versus real experience of gratitude may be different.

The authors of this paper did a follow-on study and postulate that mu-opioid receptors mediate the effects of gratitude in the brain (2).

So this means we are beginning to understand the anatomy and physiology of gratitude (quite literally).

A meta-analysis of gratitude interventions was carried out by a team of US academics (3). The results are a little complex but in summary, gratitude interventions made people feel better overall, but they did not necessarily feel more grateful or less anxious.

Does Gratitude Increase Empathy?

There are no studies looking at the relationship (if any) between gratitude and empathy. It is possible that there are case reports or small studies that have been reported at conferences or on social media, but there are no published studies linking the two.

Even extending the PubMed search to include compassion (instead of empathy) fails to reveal any studies that we can draw on.

Bottom Line

There is no evidence to suggest that gratitude increases empathy.

Does It Reduce Toxic Emotions?

Researchers from Ann Arbor studied over 1000 individuals and found that older people with high hostility scores help others less often and are less grateful (4). This is not exactly what we are talking about. This does, however, link hostility with low levels of gratitude (which is a useful piece of information). It does not tell us what would happen if these hostile individuals practiced gratitude. Would gratitude make them less hostile? I don’t know. The research does not tell us.

Fear of recurrence of cancer is an understandable but toxic emotion. In one study, sixty-seven women with early-stage breast cancer were randomly assigned to either a 6-week online gratitude intervention or a 6-week online control condition (5). Patients in the gratitude intervention experienced a significant decrease in death-related fear of death compared to the control group. That’s a win for gratitude.

Gratitude increases ‘economic patience’ and reduces impulsivity during economic decision making which inspired researchers to study conflict-driven self-control (6). (I think I might need some of that impulse shopping control). A total of 61 participants were randomly assigned to either a gratitude or happiness condition followed by a test of conflict-driven self-control. Gratitude did not help with conflict driven self-control.

Bottom Line

There is very little data (and even less positive data) on gratitude for reducing toxic emotions. At a push, a small short-term study showed that gratitude may reduce the fear of disease recurrence in breast cancer survivors but that is the extent of the data on this topic.

Does It “Improve Psychological Health”?

A group of subjects who were undergoing psychotherapy for depression and/or anxiety participated in a gratitude study (7).

One group participated in a gratitude writing intervention, which required them to write letters expressing gratitude. The therapy-as-usual control group did not perform a writing intervention. Three months later, the subjects were given a monetary gift and then asked to pass it on to a charitable cause to the extent they felt grateful for the gift. Subjects who participated in gratitude letter writing showed both behavioral increases in gratitude and significantly greater neural modulation by gratitude in the medial prefrontal cortex. (Same as the Holocaust study).

Another study evaluated the effects of four self-administered positive psychology interventions in an online setting (i.e., gratitude, three good things, three funny things, and using signature strengths in a new way) on happiness and depressive symptoms in comparison with a placebo control exercise (8).

The study enrolled a total of 163 females aged 50-79 years of age. The study participants completed the assigned interventions or the placebo control exercise for one week. The period of follow-up was  1, 3, and 6 months after completion of the study protocol. Three out of the four interventions (i.e., gratitude visit, three good things, and using signature strengths in a new way) increased happiness.

The effect of gratitude on physician health and well-being was evaluated in a 2015 study (9). A double-blind randomized controlled trial was conducted in 5 public hospitals with a follow-up to 3 months posttreatment. One hundred and two practitioners were randomly assigned to 3 conditions: gratitude journaling, hassle journaling, and nil-treatment.

Relative to the control or hassle groups, the gratitude group reported lower depressive symptoms and perceived stress.

Finally, a study in 90 Chinese students who were randomly assigned into one of three experimental conditions: gratitude, hassle, and neutral found that gratitude reduces the risk of death but does not enhance the overall sense of psychological well-being (10)

Bottom Line

The research is far from robust but available research suggests that gratitude may help psychological health.

Does it Help With Sleep?

Problems with sleep are a leading cause of concern worldwide. Lack of adequate sleep increases all-cause mortality and in increasingly viewed as a public health emergency.

British investigators studied 405 adults (40% of whom had poor sleep) and evaluated sleep quality and gratitude scores (11).

Gratitude predicted greater subjective sleep quality and sleep duration, and less sleep latency and daytime dysfunction.

British investigators also compared 2 weeks of a gratitude intervention versus no intervention in 119 young women. This short intervention increased well-being, optimism, systolic BP, and sleep but had no effect on plasma cortisol levels (12).

Bottom Line

Gratitude may help with sleep but this is based on just two very small studies.

Does it Help With PTSD?

As we are sadly aware,  school shootings are an unfortunate feature of modern life. A total of 359 students, staff and faculty enrolled in a prospective study on resilience and gratitude on post-traumatic stress following a campus shooting at Seattle Pacific University (13).

This was an observational study. There was no specific intervention. The researchers found that resilience can prevent negative outcomes while gratitude can foster positive outcomes following trauma. The authors concluded that enhancing gratitude could be a useful intervention to prevent post-traumatic stress disorders.

A 2014 study following Hurricane Katrina looked at post-traumatic stress in 84 male and female officers in Louisiana (14).

Factors such as resilience, satisfaction with life and gratitude were associated with decreased scores on the post-traumatic stress disorder checklist.

Bottom Line

Gratitude may help with post-traumatic stress disorders.

Does It Improve Self Esteem?

A total of 814 undergraduate participants (259 males and 555 females with mean age of 20.13 years) evaluated the relationship between gratitude and self-esteem (15).

The study found that gratitude had direct effects on individuals’ self-esteem. Additionally, self-esteem impacted on depression and suicidal ideation.

Bottom Line

A single study suggests that gratitude may help with self-esteem. I am always reluctant to make any recommendation based on one study.

Does Gratitude Reduce Aggression?

A single study of 18 nurses found that experiences of transgressive behavior are influenced by a number of factors including the degree of gratitude and recognition expressed by the patient (16). Hardly a great or memorable study but that is all we have to go on.

Bottom Line

There is nothing semi-useful to helps understand any links between aggression and gratitude.

Ok, I have had enough of this awful research. Like most Ph.D. waving doctors, I have a major flaw. I can dabble in qualitative research/phenomenology for a while but then get totally frustrated and want to get back to hard-core quantitative research.

The gloves are off.

Is There Any Good Research on  Gratitude?

I first searched my own area of interest, infectious diseases. There are no studies on gratitude in infectious diseases.

Next, Alzheimer’s Disease. A single study showed that gratitude helped caregivers of people with Alzheimer’s Disease (17).

A 2017 study evaluated 8 weeks of gratitude journaling in 70 heart failure patients showed that gratitude decreased markers of heart failure and increased parasympathetic heart rate variability (18).

Next to diabetes. A total of 39 adolescents with type 1 diabetes and their caregivers were randomized to a positive psychology intervention (gratitude, self-affirmation), small gifts, and parent affirmations to boost positive affect (19). Outcome measures included frequency of blood glucose monitoring, quality of life, and glycemic control. The study found that gratitude had no effect on glucose control but did positively affect adherence and glucose monitoring.

Diabetic patients with sub-optimal adherence to medications completed a series of exercises (eg, writing a gratitude letter, performing acts of kindness) (20).  Participants rated the exercises as helpful and they reported improvements in optimism, gratitude, depression, anxiety, physical function, self-care, and health behaviors. Unfortunately, we have no insights into the actual glycemic control.

Is Gratitude Safe?

There is so little known about the science of gratitude and even less about the safety profile of gratitude. I would hazard a guess that it is important to be very sensitive suggesting gratitude to patients who are sad, grieving or sick.

Conclusion

Gratitude is slowly creeping into medical practice. We have very limited qualitative research on gratitude. We have almost no hardcore quantitative data on gratitude for common medical conditions. As a mainstream doctor, I would be really interested in the impact of gratitude on more formal clinical outcomes, biochemical parameters, and radiological investigations.

As things stand and based on what we know, the professional side of me cannot recommend gratitude to my patients. Meantime, the private me will continue to send “Thank You” cards and do gratitude journalling each morning.