Therapy
What Acceptance and Commitment Therapy Research Tells Us
1000 randomized controlled trials on acceptance and commitment therapy.
Posted September 2, 2024 Reviewed by Lybi Ma
Key points
- Acceptance and commitment therapy, ACT, has been the subject of research for more than 40 years.
- The number of randomized controlled trials on ACT recently passed 1,000.
- ACT research has gone beyond the confines of psychological disorders, embracing a broader vision.
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If you were to visit a psychotherapist in the 1970s or '80s, you might get some peculiar advice. Eliminate negative thoughts. Control your feelings. Just focus on overt behavior. Lessons like these represented the height of what researchers back then knew about human well-being; it’s no wonder that they are still often found in cultural conversations on mental health 40 years later.
Nowadays, however, psychologists know better. Rather than forcing positive thoughts to eliminate negative ones, we are often better advised to learn how to step back from our thoughts (both negative and positive ones) and use useful ones. And rather than controlling our feelings, or trying to relax them away, we can learn to embrace them and learn from them, while focusing our actions on what we truly care about.
Acceptance and commitment therapy (ACT) was a big part of this change. It’s been the subject of process and outcome research for more than 40 years. It is evidence-based and effective in addressing a wide range of mental and behavioral health issues. And quite recently, ACT research crossed an important milestone, as the number of randomized controlled trials on ACT passed 1,000. Randomized trials are not the end-all and be-all of research (the topic for a future post) but they are widely considered to be a kind of gold standard in intervention research because when they are done properly they allow one to observe causal effects.
Reaching such a milestone is a good time to pause and reflect on what we have learned about ACT, and to consider where we might go from here in the future. This is exactly what I and my colleague Grant King did in our recently published article “Acceptance and commitment therapy: What the history of ACT and the first 1000 randomized controlled trials reveal.” It’s not too technical even for general readers; it’s open-access and anyone can read it for free.
Here is what we learned from analyzing the first 1000 randomized controlled trials on acceptance and commitment therapy.
Lesson #1 ACT Goes Far Beyond Psychological Disorders
ACT was never just about the “mental health disorders” (anxiety, depression, and so on) that might be found in diagnostic manuals such as the DSM (Diagnostic Statistical Manual) or the ICD (International Classification of Diseases). ACT was meant to address such things while at the same time going beyond traditional therapy targets toward learning how to empower human prosperity in such areas as dealing with chronic illness, improving personal relationships, enhancing workplace performance, or even reducing societal prejudice. The paper describes how early ACT research was mostly focused on basic principles, processes, and components in hopes that these ideas and methods would eventually apply wherever the human mind goes.
Now, 40 years later that has happened. Only 21 percent of the first 1,000 ACT trials have been focused on the DSM. Nearly twice as many are focused on behavioral health issues (exercise, weight, coping with physical illness, chronic pain); another similarly large number on social problems or performance. Indeed ACT is now listed by science agencies as being evidence-based in many of these areas.
That’s cool.
This breadth comes because ACT promotes psychological flexibility, the ability to open up to one’s own experience, adapt to changing circumstances, and live by one's values. Increases in psychological flexibility make ACT relevant to the goals of almost anyone, including all of those who have issues that may not fit into traditional diagnostic categories.
Lesson #2 We’ve Learned From Low- and Middle-Income Countries
Most of the randomized controlled trials on ACT come from high-income countries but a surprisingly large percentage (45 percent) come from lower and middle-income countries (LMICs). Their ACT research has taken on a different character, often prioritizing well-being and quality of life over symptom reduction.
The global expansion of ACT research has highlighted the importance of understanding how psychological interventions function in diverse cultural contexts. The careful and at times slow effort to build out the psychological flexibility model has paid off because it has made it easy to culturally modify ACT. For example, ACT principles such as being more open, aware, and focused on your values resonate with all major religions. Thus, in Iran, ACT interventions can make their points using stories drawn from Islamic teaching, while in China they may be drawn from Daoism, Confucianism, or Buddhism.
Some important problems that are commonly studied in LMICs such as the distress of infertility in couples who wish to have children are rarely studied in high-income countries because funding agencies do not view them as “disorders.” We as a community need to learn from LMICs and ACT research has led the way by providing ideas and methods that have spread globally. This holds out hope that we can learn to better serve people from various cultural backgrounds in a world that is becoming increasingly diverse.
Lesson #3 Mental Resilience Can Be Supported in Many Ways
Early ACT research was limited to face-to-face interventions in an individual or group context. As ACT research has expanded, however, it is helpful when delivered by books, phone calls, websites, apps, or various forms of self-help. Because ACT research is so voluminous even new areas such as these quickly reach substantial numbers. For example, just studies on the internet or app-based ACT interventions already number about 50 studies, a number that exceeds the total number of studies for many interventions of note.
Lesson #4 We Need to Consider Non-Indexed Studies
As ACT research continues to grow, we need to consider studies that are not indexed in major databases. Non-scientists may not realize that few people read specific journals cover to cover anymore. Indeed the phrase cover to cover does not even apply because many journals are all electronic. Their content is known because internet search engines code their content (they “index” the studies). Some 85 percent of the ACT LMIC research is non-indexed. These studies, often published in non-English journals or regions with limited access to global research networks, can provide valuable insights into how ACT functions in diverse cultural contexts, and thus mustn’t be neglected.
While there are legitimate concerns about the quality of some non-indexed studies, dismissing them outright could lead to a skewed understanding of ACT's global impact. Indeed, we’ve documented exactly that in a second study in the journal Behavior Therapy that will be published later this month. The history of indexing shows clearly that the major companies that decide what gets indexed have often cut off non-English journals simply due to bias. For example, one major indexing company only decided to index Korean journals 10 years ago! In today’s global era, we need a more nuanced approach – one that assesses the quality of each study on a case-by-case basis while recognizing the unique contributions that non-English research can offer.
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The first 1,000 randomized controlled trials show that ACT research has gone beyond the confines of psychological disorders, embracing diverse cultural contexts, using a range of media, and considering the contributions of all. These steps are essential for ensuring that all people can benefit from greater mental resilience, regardless of their unique challenges, individual backgrounds, or international whereabouts.
References
Steven Hayes, Ph.D., originated and co-developed acceptance and commitment therapy.
Hayes, Steven & King, Grant. (2024). Acceptance and Commitment Therapy: What the History of ACT and the First 1,000 Randomized Controlled Trials Reveal. Journal of Contextual Behavioral Science. 33. 100809. 10.1016/j.jcbs.2024.100809.